This conversation has been merged. Please reference the main conversation: Photoshop 2020: Batch is removing parts of names after . in name
Previous to the new 2020 update, I could open these files in photoshop and run an action that would tweak various things then save a tif version to a folder on my desktop. But now when I run the same action (or try to make a new action), the files save as 'render.tif' instead of 'render.0001.tif', so running the action on ten files in a row just repeatedly saves 'render.tif' over itself again and again.
That's a bizarre behavior change and affects my workflow several times a day. I assume it must be bug because It makes no sense for Photoshop to ever silently change a file name like that.