Issues while saving PDFs Acrobat DC

Hello 

I'm having some weird issues while saving PDFs with Acrobat Reader DC.

Randomly, I get the message "The file maybe read only. The document could not be saved. This file is already open or in use by another application"

This happens randomly. Sometimes when I click on Save, it simply saves the file. 

But, then for the same file, sometimes it prompts me for the location and whether or not I would like to overwrite the existing file.

If I say Yes, it would throw the above error.

This happens randomly.

Another issue that I have seen - If I say Yes to overwrite the existing file, Acrobat renames the file by pre-populating a series of random letters followed by .to

Then if I close the Acrobat reader, and look for that tmp file, it's gone.

I'm running Win 10 pro version 20H2 with the latest version of Acrobat Reader 2021.001.20145

I have tried to repair the installation and reboot (no change)

Change preview pane on/off in explorer (no change)

Saw the exact same behavior on a different Win10 machine.

I'm not sure how to fix this as it's happening randomly.  

Please advise.