Shift+Enter fails to set focus inside the next cell if it already exists

Repro:
Type aaa in the first cell.
Press Shift+Enter to create new cell and jump to it.
Type bbb (in the second cell) - everything works as usual

Now repeat that again:

Move cursor inside the first cell
Type aaa in the first cell.
Press Shift+Enter.
Type bbb (in the second cell) - Instead of adding text, Jupyter is now creating new cells. That's because it failed to set the focus inside the cell.

Expected behavior:
I expect Shift+Enter works the same regardless of whether the next cell already exists or not. It should set focus inside the cell editor, not outside.

It's super annoying. It was working properly before (on jupyter I had on other PCs), but now it's not working.