I've seen this occur a few times in #mentor-requests, but mentoring requests for the Forth exercise receive the Forth reaction because we have an unmaintained Forth track. I skimmed the exercise folders in the problem-specifications repo, and I think this is the only exercise with this issue.
If we do want to resolve this, we'd still want Bob to react to mentoring request messages to tag the correct language. For the example Gleam: https://exercism.org/mentoring/requests/gibberish => Forth (BNAndras), I'm thinking we do a check if the message we're parsing contains an Exercism mentoring request URL and then remove everything after that. That might help too if the user name mirrors a track so Gleam: https://exercism.org/mentoring/requests/gibberish => Forth (BNAndras) and Gleam: https://exercism.org/mentoring/requests/gibberish => Yacht (Forth) becomes "Gleam: " in both cases. Then Bob can still react accordingly.