The GetBlockedStatus hook was deprecated in T229035, because it works by manipulating public block properties on the User object, and allows for these to become inconsistent (see original task for more details).
RegexBlock should be updated to use the GetUserBlock hook instead. GetUserBlock passes in a clone of the user, so manipulating properties on this object will not have any effect. GetUserBlock passes in the block, which may be null or some type of AbstractBlock - this object should be changed if necessary.
Until this update is made, unit tests should be updated to expect a deprecation warning to be emitted about the use of getBlockedStatus.