I have enabled HTTP2 with self signed certificate and getting exceptions when closing browser(Firefox/Chrome both on MacOS Sierra) and sometime(intermittently) stopping server.

Exception while closing Chrome

2016-11-17_11:23:49.558 [XNIO-1 I/O-6] DEBUG io.undertow.request.io - UT005013: An IOException occurred
java.io.IOException: javax.net.ssl.SSLException: Inbound closed before receiving peer's close_notify: possible truncation attack?
at io.undertow.protocols.ssl.SslConduit.notifyReadClosed(SslConduit.java:614)
at io.undertow.protocols.ssl.SslConduit.doUnwrap(SslConduit.java:710)
at io.undertow.protocols.ssl.SslConduit.read(SslConduit.java:567)
at io.undertow.conduits.IdleTimeoutConduit.read(IdleTimeoutConduit.java:201)
at org.xnio.conduits.ConduitStreamSourceChannel.read(ConduitStreamSourceChannel.java:127)
at io.undertow.server.protocol.framed.AbstractFramedChannel.receive(AbstractFramedChannel.java:369)
at io.undertow.server.protocol.http2.Http2ReceiveListener.handleEvent(Http2ReceiveListener.java:102)
at io.undertow.server.protocol.http2.Http2ReceiveListener.handleEvent(Http2ReceiveListener.java:55)
at org.xnio.ChannelListeners.invokeChannelListener(ChannelListeners.java:92)
at io.undertow.server.protocol.framed.AbstractFramedChannel$FrameReadListener.handleEvent(AbstractFramedChannel.java:923)
at io.undertow.server.protocol.framed.AbstractFramedChannel$FrameReadListener.handleEvent(AbstractFramedChannel.java:904)
at org.xnio.ChannelListeners.invokeChannelListener(ChannelListeners.java:92)
at org.xnio.conduits.ReadReadyHandler$ChannelListenerHandler.readReady(ReadReadyHandler.java:66)
at io.undertow.protocols.ssl.SslConduit$SslReadReadyHandler.readReady(SslConduit.java:1128)
at org.xnio.nio.NioSocketConduit.handleReady(NioSocketConduit.java:89)
at org.xnio.nio.WorkerThread.run(WorkerThread.java:567)
Caused by: javax.net.ssl.SSLException: Inbound closed before receiving peer's close_notify: possible truncation attack?
at sun.security.ssl.Alerts.getSSLException(Alerts.java:208)
at sun.security.ssl.SSLEngineImpl.fatal(SSLEngineImpl.java:1666)
at sun.security.ssl.SSLEngineImpl.fatal(SSLEngineImpl.java:1634)
at sun.security.ssl.SSLEngineImpl.closeInbound(SSLEngineImpl.java:1561)
at io.undertow.protocols.ssl.ALPNHackSSLEngine.closeInbound(ALPNHackSSLEngine.java:279)
at io.undertow.protocols.ssl.SslConduit.notifyReadClosed(SslConduit.java:612)
... 15 common frames omitted

Exception while closing Firefox

2016-11-17_11:33:08.641 [XNIO-1 I/O-6] DEBUG io.undertow.request - Closing HTTP2 channel to /0:0:0:0:0:0:0:1:50942 due to broken read side
java.io.IOException: Connection reset by peer
at sun.nio.ch.FileDispatcherImpl.read0(Native Method)
at sun.nio.ch.SocketDispatcher.read(SocketDispatcher.java:39)
at sun.nio.ch.IOUtil.readIntoNativeBuffer(IOUtil.java:223)
at sun.nio.ch.IOUtil.read(IOUtil.java:192)
at sun.nio.ch.SocketChannelImpl.read(SocketChannelImpl.java:380)
at org.xnio.nio.NioSocketConduit.read(NioSocketConduit.java:289)
at io.undertow.protocols.ssl.SslConduit.doUnwrap(SslConduit.java:700)
at io.undertow.protocols.ssl.SslConduit.read(SslConduit.java:567)
at io.undertow.conduits.IdleTimeoutConduit.read(IdleTimeoutConduit.java:201)
at org.xnio.conduits.ConduitStreamSourceChannel.read(ConduitStreamSourceChannel.java:127)
at io.undertow.server.protocol.framed.AbstractFramedChannel.receive(AbstractFramedChannel.java:369)
at io.undertow.server.protocol.http2.Http2ReceiveListener.handleEvent(Http2ReceiveListener.java:102)
at io.undertow.server.protocol.http2.Http2ReceiveListener.handleEvent(Http2ReceiveListener.java:55)
at org.xnio.ChannelListeners.invokeChannelListener(ChannelListeners.java:92)
at io.undertow.server.protocol.framed.AbstractFramedChannel$FrameReadListener.handleEvent(AbstractFramedChannel.java:923)
at io.undertow.server.protocol.framed.AbstractFramedChannel$FrameReadListener.handleEvent(AbstractFramedChannel.java:904)
at org.xnio.ChannelListeners.invokeChannelListener(ChannelListeners.java:92)
at org.xnio.conduits.ReadReadyHandler$ChannelListenerHandler.readReady(ReadReadyHandler.java:66)
at io.undertow.protocols.ssl.SslConduit$SslReadReadyHandler.readReady(SslConduit.java:1128)
at org.xnio.nio.NioSocketConduit.handleReady(NioSocketConduit.java:89)
at org.xnio.nio.WorkerThread.run(WorkerThread.java:567)
2016-11-17_11:33:08.642 [XNIO-1 I/O-6] DEBUG io.undertow.request - Closing HTTP2 channel to /0:0:0:0:0:0:0:1:50942 due to broken write side
java.nio.channels.ClosedChannelException: null
at io.undertow.protocols.ssl.SslConduit.write(SslConduit.java:377)
at io.undertow.conduits.IdleTimeoutConduit.write(IdleTimeoutConduit.java:129)
at org.xnio.conduits.ConduitStreamSinkChannel.write(ConduitStreamSinkChannel.java:154)
at io.undertow.server.protocol.framed.AbstractFramedChannel.flushSenders(AbstractFramedChannel.java:637)
at io.undertow.server.protocol.framed.AbstractFramedChannel.flush(AbstractFramedChannel.java:718)
at io.undertow.server.protocol.framed.AbstractFramedChannel.queueFrame(AbstractFramedChannel.java:711)
at io.undertow.server.protocol.framed.AbstractFramedStreamSinkChannel.queueFinalFrame(AbstractFramedStreamSinkChannel.java:256)
at io.undertow.server.protocol.framed.AbstractFramedStreamSinkChannel.shutdownWrites(AbstractFramedStreamSinkChannel.java:241)
at io.undertow.protocols.http2.Http2Channel.sendGoAway(Http2Channel.java:704)
at io.undertow.protocols.http2.Http2Channel.handleBrokenSourceChannel(Http2Channel.java:544)
at io.undertow.server.protocol.framed.AbstractFramedChannel.markReadsBroken(AbstractFramedChannel.java:820)
at io.undertow.server.protocol.framed.AbstractFramedChannel.receive(AbstractFramedChannel.java:475)
at io.undertow.server.protocol.http2.Http2ReceiveListener.handleEvent(Http2ReceiveListener.java:102)
at io.undertow.server.protocol.http2.Http2ReceiveListener.handleEvent(Http2ReceiveListener.java:55)
at org.xnio.ChannelListeners.invokeChannelListener(ChannelListeners.java:92)
at io.undertow.server.protocol.framed.AbstractFramedChannel$FrameReadListener.handleEvent(AbstractFramedChannel.java:923)
at io.undertow.server.protocol.framed.AbstractFramedChannel$FrameReadListener.handleEvent(AbstractFramedChannel.java:904)
at org.xnio.ChannelListeners.invokeChannelListener(ChannelListeners.java:92)
at org.xnio.conduits.ReadReadyHandler$ChannelListenerHandler.readReady(ReadReadyHandler.java:66)
at io.undertow.protocols.ssl.SslConduit$SslReadReadyHandler.readReady(SslConduit.java:1128)
at org.xnio.nio.NioSocketConduit.handleReady(NioSocketConduit.java:89)
at org.xnio.nio.WorkerThread.run(WorkerThread.java:567)
2016-11-17_11:33:08.643 [XNIO-1 I/O-6] DEBUG io.undertow.request - Closing HTTP2 channel to /0:0:0:0:0:0:0:1:50942 due to broken write side
java.nio.channels.ClosedChannelException: null
at io.undertow.server.protocol.framed.AbstractFramedStreamSinkChannel.flush(AbstractFramedStreamSinkChannel.java:345)
at io.undertow.protocols.http2.Http2Channel.sendGoAway(Http2Channel.java:705)
at io.undertow.protocols.http2.Http2Channel.handleBrokenSourceChannel(Http2Channel.java:544)
at io.undertow.server.protocol.framed.AbstractFramedChannel.markReadsBroken(AbstractFramedChannel.java:820)
at io.undertow.server.protocol.framed.AbstractFramedChannel.receive(AbstractFramedChannel.java:475)
at io.undertow.server.protocol.http2.Http2ReceiveListener.handleEvent(Http2ReceiveListener.java:102)
at io.undertow.server.protocol.http2.Http2ReceiveListener.handleEvent(Http2ReceiveListener.java:55)
at org.xnio.ChannelListeners.invokeChannelListener(ChannelListeners.java:92)
at io.undertow.server.protocol.framed.AbstractFramedChannel$FrameReadListener.handleEvent(AbstractFramedChannel.java:923)
at io.undertow.server.protocol.framed.AbstractFramedChannel$FrameReadListener.handleEvent(AbstractFramedChannel.java:904)
at org.xnio.ChannelListeners.invokeChannelListener(ChannelListeners.java:92)
at org.xnio.conduits.ReadReadyHandler$ChannelListenerHandler.readReady(ReadReadyHandler.java:66)
at io.undertow.protocols.ssl.SslConduit$SslReadReadyHandler.readReady(SslConduit.java:1128)
at org.xnio.nio.NioSocketConduit.handleReady(NioSocketConduit.java:89)
at org.xnio.nio.WorkerThread.run(WorkerThread.java:567)
2016-11-17_11:33:08.643 [XNIO-1 I/O-6] DEBUG io.undertow.request.io - UT005013: An IOException occurred
java.io.IOException: Connection reset by peer
at sun.nio.ch.FileDispatcherImpl.read0(Native Method)
at sun.nio.ch.SocketDispatcher.read(SocketDispatcher.java:39)
at sun.nio.ch.IOUtil.readIntoNativeBuffer(IOUtil.java:223)
at sun.nio.ch.IOUtil.read(IOUtil.java:192)
at sun.nio.ch.SocketChannelImpl.read(SocketChannelImpl.java:380)
at org.xnio.nio.NioSocketConduit.read(NioSocketConduit.java:289)
at io.undertow.protocols.ssl.SslConduit.doUnwrap(SslConduit.java:700)
at io.undertow.protocols.ssl.SslConduit.read(SslConduit.java:567)
at io.undertow.conduits.IdleTimeoutConduit.read(IdleTimeoutConduit.java:201)
at org.xnio.conduits.ConduitStreamSourceChannel.read(ConduitStreamSourceChannel.java:127)
at io.undertow.server.protocol.framed.AbstractFramedChannel.receive(AbstractFramedChannel.java:369)
at io.undertow.server.protocol.http2.Http2ReceiveListener.handleEvent(Http2ReceiveListener.java:102)
at io.undertow.server.protocol.http2.Http2ReceiveListener.handleEvent(Http2ReceiveListener.java:55)
at org.xnio.ChannelListeners.invokeChannelListener(ChannelListeners.java:92)
at io.undertow.server.protocol.framed.AbstractFramedChannel$FrameReadListener.handleEvent(AbstractFramedChannel.java:923)
at io.undertow.server.protocol.framed.AbstractFramedChannel$FrameReadListener.handleEvent(AbstractFramedChannel.java:904)
at org.xnio.ChannelListeners.invokeChannelListener(ChannelListeners.java:92)
at org.xnio.conduits.ReadReadyHandler$ChannelListenerHandler.readReady(ReadReadyHandler.java:66)
at io.undertow.protocols.ssl.SslConduit$SslReadReadyHandler.readReady(SslConduit.java:1128)
at org.xnio.nio.NioSocketConduit.handleReady(NioSocketConduit.java:89)
at org.xnio.nio.WorkerThread.run(WorkerThread.java:567)

Please let me know if you need more information.