P: File extension (ex. jpg) not changing during format change after upgrade to macOS 10.15 Catalina

Download the latest update which has been out for at least a week -- it should solve your problem?????

I am experiencing the exact same issue and it is driving me absolutely insane. I've wasted so much time having to re-save and type the format on my own too.

Just update Photoshop. It's been fixed.

I am so confused as to what to do even after reading all of your comments and suggestions. Maybe I make more work for myself by doing it this way but its just the way I have saved files since the beginning. I create 3 different folders within a clients raw images. a print folder with are my jpeg images, social media folder which are my correct size and saved as png and a psd folder to save my images with the layers incase I need to go back and adjust.  I can't open any files I have saved as .psd. (my saved layers images) in photoshop. I have also saved my images as jpeg using every way thats been described and they aren't saving correctly. I am at an absolute loss as to what to do. Im more concerned about my psd layer files than any other. None of this was an issue until the update to Catalina. Please help!!

Actually it has taken two weeks.

Glad they were so responsive to this issue. After only a couple of days, it was a serious hassle!

Yes, there was an update for Photoshop this morning...I have automatic updates checked, but I went in and looked for it and updated manually.  I don't know yet if the update has solved the problems, but I assume that it will.

Don't know what to tell you but there was an update for me, I manually checked it (I don't have automatic updates activated). So I updated Photoshop 7 hours ago and the update resolved this issue for me.

This is great stuff.