I made no changes to the forum. But you are right. I also have to double-tap on iPad with iOS 15.7 and only single tap on iPhone with iOS 16.0.2. Also no problem on iPad with iOS 12.5.6. So I guess it is an iOS 15.7 issue.
Anyway, I am already on the newest version of the forum software. So the only thing we can do is wait for a fix from iOS or the forum.