The arrow down/up issue should be fixed via:
The in:title search is still there. If you want to trigger it by typing the full string, you just need to add a space at the end and it will trigger a search.
There is also a quicker option. Type 86 in:, wait briefly for the suggestions to show up, then hit arrow down (to select the first suggestion, which is 86 in:title) and then hit Enter. It needs some muscle memory retraining, but it’s a couple of keystrokes shorter.