the following predicates (similar than the ones found in the documentation page fails to resolve to true when appropriate:

path-template[value="/_authtokens/{username}"] and equals[%u, ${username}]
regex[pattern="/_authtokens/(.*?)", value=%U, full-match=true] and equals[%u, "${1}"]

example:
authenticated user with username "admin"
GET /_authtokens/admin should resolve to true, but it actually resolves to false.

I'm sure 100% that the latter was working with undertow-core 1.1.1.Final (I think the the first one was failing as well with 1.1.1)