P: Batch is removing parts of names after . in name

Photoshop 2020 Actions with Save As steps will save incorrect File names when Document names contain "."  where prior versions of Photoshop work correctly. 

Reported is Photoshop Forum
https://community.adobe.com/t5/photoshop/photoshop-21-0-2-batch-action-file-type-change-error-period-in-file-name/td-p/10811761

I don't use Batch in my action. My action knocks down 16bit ProPhoto files to 8bit sRGB. Then saves the file to a different folder. This is where the problem arrises. Somewhere when it goes to a different folder. If I didn't have the file going to a different folder and just saving over the original, the problem doesn't exist. My action is Crop, convert to sRGB, 8bit, Save (not save as.)

There is a known issue with Bridge Batch Rename removing the file extension with a double dot in the filename. I wonder if this is related?

I have a series of 3d renders with sequential names like...

render.0001.exr
render.0002.exr
render.0003.exr  etc..

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.

Try using Scripts > Image Processor... as a workaround

That should preserve your file naming.

Myself and another coworker as having the same saving issue as part of an action. Removes any text after the first . (period). Saving 8 bit tifs from 16 bit tifs. Action has been working for at least four years with minor changes. No changes in the past two years. I am running Photoshop 2020 on a Mac Pro (Mid 2012) with macOS High Sierra 10.13.6. Co-worker is running Photoshop 2020 on a MacPro (Late 2013) with macOS Mojave.