"Properties of the Message have Changed" Prompt Outlook365

One of my users keeps getting "The properties of the message have been changed" prompt when forwarding/replying in Outlook.

This user recently received Adobe Acrobat Pro and it only has occurred after this installation.

I believe Googling has shown that this was solved in a recent Office/Outlook patch, but the user is currently on "Version 2106 (Build 14131.20332 Click-to-run)" and is still getting the issue.

Any help is appreciated.