when logging using an ExtLogRecord that contains a Throwable from a Class that has no package(default package), the stack trace was missing newlines.

bug is in org.jboss.logmanager.formatters.Formatters.java in the method:

private void renderExtended(final StringBuilder builder, final StackTraceElement element, final Map<String, String> cache)

lines 418 -> 420 are:
if (dotIdx == -1)

{ return; }

which allows the routine to return without appending a newline... it might be changed to:

if (dotIdx == -1)

{ builder.append(NEW_LINE); return; }