Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
I was finally able to resolve this on the two devices affected by carrying out the following:
- Uninstalling Teams
- Clearing out the Teams folders from the users profiles
- Completely uninstalling Office 365
- Reinstalling Office 365
- Updating Office 365
- Installing Teams using the latest install files
Seems a lot to get an application that can be installed independent to Office to work, but this has resolved the issue for both devices.