I’m not actually sure it “regressed” as in the code didn’t change, we still have autofocus on the input and it’s still working for me “the first time” but not on the second time.
I just pushed a commit which will make this kind of behaviour much more reliable:
https://github.com/discourse/discourse/commit/4e0c06a0b16acaf88c3899f829636ac0f1a254a9