User reported problem with getting work jdbc_realm with bcrypt mapper. He had configured org.wildfly.security to log TRACE messages, but log does not provide any useful information regarding mapping password from DB.
In this case seems problem was in mixing base64 vs. modular crypt format.
Looking into PasswordKeyMapper there is a lot of logic and lot of steps which can get wrong. So logging some TRACE messages can hint user what is going on and what went wrong.
Also I have noticed there is unhandled exception. Please at least log some TRACE message.