Save for web in CC 2020 no longer highlights only filename, leaving extension. I have to type them!!

Very frustrating. I use the save for web option constantly, and I noticed awhile ago that when I hit the save button, it USED to highlight just the actual file name in the top, leaving the .jpg, or .png alone. Now, it auto selects the entire box extension and all, so when I start typing, I have to manually add the extension too. Of course I forget half the time and have to go back and add it.

This is not happening in Save As... or any other dialog box, just the Save for Web. See attached. 

I don't remember when it happened, but within the last few months. I just put up with it until now. I'm on a Mac, Mojave, imac pro, latest version of Photoshop as of today. 

Any ideas? Or just a bug?