This has happened to me twice in the past couple of days, and sporadically over the last several months. I use Photoshop to create email layouts so oftentimes what I do is open the previous version of a design and do a "Save As" to keep the same template. All my files are named after the date. I opened my 1-30-2020 file, selected "Save As," named the file 1-31-2020, and started working. I happened to look at the tab for the file and noticed the filename still said "1-30-2020," effectively saving over my older file with the new work that I had done! I thought at first that maybe I'd forgotten to do "Save As" but when I went back in my folders, there was the file 1-31-2020, right where I saved it in the first place. Not sure what is going on, but it's an annoying little glitch that causes me to lose and accidentally save over previous work.