No worries, it's just my speculation... Not a fact... Molly for instance diverged from Signal enough to have a different fingerprint in their api calls to the server.
Another possibility they may decide to refuse clients unless signed by signal... Please note this is NOT the case today and they never even hinted that they will ever do something like that... Still technically possible.
Again none of that should be a reason not to use a fork. Other reasons like trusting another part are way more important... I bought it up just so people have full picture