According to your description, I have two questions as below.
- Are your Microsoft 365 apps working properly?
- Do other users have this issue on their PCs?
> Is it possible, that a MS update messed up the activation status on computer a? Is there any fix that will get it into the state that computer b is in?
<< As far as I know, MS update for Microsoft 365 may not the cause of Software Licensing Service reported that the grace period expired.
> they are activated, signed in using my domain credentials.
<< You could try to check the issue in an environment away from the domain of your organization, such as logging in your account on a test PC or create a new Windows account that not in the domain of your organization.
In addition, it is suggested to "Reset Microsoft 365 Apps for enterprise activation state" to check this issue.
If the above do not work, please try to uninstall and reinstall it. Then log in to your account to reactivate.
Any updates, please let me know.
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