as an update, it's not just third-party apps, this problem affects even the "native" Apple Screen Time "App Limit" feature; Reddit is full of threads of people complaining about this starting with iOS 26.2

iOS 26.3 beta 3 might have a new (arguably worse?) behavior where instead of all limits blocking instantly on DEVICE pickup, each limit blocks instantly separately only when you open the app so if you have two separate limits (YouTube and Instagram), YouTube will block when its opened for the first time while leaving Instagram unaffected, until you open Instagram for the first time (where then that will also instantly block)

iOS 26.3 RC does not seem to fix the problem

Yes, same here. iOS 26.4 looking stable so far. Thank you for the fixes Apple devs 🙏

Unfortunately, just got the latest 26.4 beta 3(?) that released yesterday and am again getting the problem. iOS 26.4 (23E5223f)

unfortunately, iOS 26.4 (final version) also has the bug that's iOS 26.2, iOS 26.3 and iOS 26.4 (3-4 months) of limits automatically activating most mornings without reaching the limit, and this also affects the default Apple Screen Time

How are people doing on iOS 26.5? So far so good, but this happened with the first 26.4 release too: it seemed to be fixed, but then (maybe) something got reverted.

+1 AFAIK the ability to put "Apps With Screen Time Access" behind a Screen Time Passcode is a new thing since iOS 26.4 (?). I'm currently on iOS 26.5 Beta 2 and this particular part works fine (it presents Screen Time passcode when trying to disable an apps Screen Time access). However, the introduction of this introduced a similar bug where if you access the apps settings (not Screen Time settings), you can circumvent the Screen Time Passcode by using the "Screen Time Restrictions" toggle. FB22463959 is feedback number. The feedback for Apple is actually relatively simple (politics aside): just don't show the "Screen Time Restrictions" toggle in apps settings. This is how it actually was before. This is just a typical engineering/product issue where introducing new features introduces more bugs. Keeping it simple == less bugs (now and in the future).

+1 a lot of developers report instability around Screen Time API's and this can fix a lot of headache for both Apple and devs