Calling this "severe" feels overblown. It's a UI mismatch likely caused by using multiple caches that are out of sync. I feel like every engineer on this site has encountered this exact bug at one point or another. It's an easy one to run into, especially in bigger orgs.

The second screenshot with “1 3 Next” seems pretty hard to justify.

Taking care that such incongruent representations can’t happen even in the face of inconsistent backend caches is part of proper UI state management.

Yes but in the case of GH, it also happens in cases where the data is old: not just a temporary drift.