Diagnostic lines, in the source TAP file, look like

not ok     3 foo.lux
    # FAIL at line 13:34
    # expected
    #   ==0==
    # actual fail pattern matched "==1=="

but when checking the TAP results in the Jenkins UI (tap-plugin views), it comes out as

# FAIL at line 13:34
# expected
#   ==0==
# actual fail pattern matched "==1=="

The same happens with whitespaces after the # sign, which is even worse (think pretty-printed JSON output).