I'm using Teams (Version 1.4.00.29478) on macOS (BigSur 11.6) and I'm finding the select all text shortcut (CMD + A) isn't working. The cut, copy, paste and undo shortcuts all work fine, it's just select all which isn't working. I use it all the time so it's quite annoying. It works in all the other apps I've tested, including other Office apps like Word, Excel and Outlook. I've checked the Teams specific shortcuts but nothing is mapped to CMD + A and I've double checked the shortcut app I use (BetterTouchTools) and it's also not using CMD + A.
I managed to identify that it was something to do with the VShieldScanner process, which is part of the McAfee software my work installed on the machine. When I turned it off and restarted Teams CMD + A started working again. After turning McAfee back on and restarted Teams again it's still working. Will keep an eye on it.