In our testing environment we see occasional aborted HTTP2 requests since chrome added a few request headers in version 76. After a lengthy debate and debugging, we came to the conclusion that this is likely to be caused by an off-by-one error in HpackDecoder in Undertow at this line:
https://github.com/undertow-io/undertow/blob/9b25a43a913935077c51581f184b18e990981078/core/src/main/java/io/undertow/protocols/http2/HpackDecoder.java#L270

It looks like this line should read:

if (index > Hpack.STATIC_TABLE_LENGTH + filledTableSlots) {

The discussion at the chromium bug tracker can be found at:
https://bugs.chromium.org/p/chromium/issues/detail?id=992320