Tapping some URLs will inconsistently get you to the page too without having to do any URL replacement. I don’t think there’s any intended logic there, just some bugs in the way URLs get handled hopping from social media app to browser to social media app since most of them try to keep you silo’d in.
What you're describing is a bit different(It's probably implemented like this because old videos that weren't initially uploaded as shorts were absorbed into shorts if they fit the correct criteria)
As far as I can tell YouTube itself tends to be pretty similar, but features come first for Android, I think PiP for shorts is out of beta in Android, but as you mentioned just getting tested on iOS
I commend this level of diligence! The feature is only 2 weeks old: https://blog.youtube/news-and-events/new-youtube-premium-fea...