Why Find doesn' work at all in one folder and does perfectly fine in another?

You can see I have two files with "edge" in their names and Ctrl+F menu doesn't find anything. In fact it doesn't work at all. With any search parameter. Then in other folder it works just fine. Moreover it worked in this same folder a week ago. What am I missing? I have this unreliable behaviour for years.
ps. I renamed the folder , re-opened Bridge and Find works just fine. Re-named the folder back to original name and it's still working. It's a weird fix but works at least . Still wonder why? And how can I make it work without all those extra troubles ?
