ApiUserBlockedTest expects error messages like 'blockedtext', 'no-permission' to be produced on block. However, in ApiBase, addBlockInfoToStatus() replaces blockedtext with apierror-blocked. Thus the test is broken. This seems to be added in commit ace0338421b6f100d4fde475206d165bd0b3afeb.
I thought Lexeme was now in gate? How did the core change land?
I have no idea... Something seems to be wrong there. There was also a case recently where Lexeme had wrong class name and it wasn't detected. I think some CI config steps are missing for this extensions still, but not sure which.