Previously it only restored tabs in the current window (as there is a separate Ctrl+Shift+N to open a closed window), but now it also opens windows, so closing a single-tab window effectively locks you out of spamming Ctrl+Shift+T as it restores that instead. And stops (as it was a single-tab window from start, there's no tab to re-open there).
Am sorry if it sounds like a rant, but that "update" was inconvenient enough for me to rollback to FF115 and disable updates, so...