lol that sounds like an existing old-YouTube bug that ReVanced also suffered of a while ago.
You’d wanna use an up-to-date version, but that’s hard on such an old android version
I’d suggest - even tho it isn’t 1:1 the same - that you export your subscriptions from Google and import them either into LibreTube (closer to the official YT app) or NewPipe.
Because LibreTube uses the (awesome) Piped Project to load videos and info, you can also sync data using it and your favourite piped instance. (piped.video, piped.smnz.de, piped.adminforge.de are personal recommendations)