I'm having this issue right now were I can't login with the admin account to a computer that was disjoined/disconnected from AzureAD. It was disconnected/disjoined from AzureAD on purpose, as it was no longer required.
I'm not familiar with AzureAD, but at least in the old-school I remember that when you removed a computer from the AD domain you were asked to setup a new password for your local admin account. The tech that did this says he did not get asked to setup a new password when he removed the machine from AzureAD.
So I'm inclined to think the following:
Removing the machine from AAD does not require a password change on local admin by design, and we never knew the password in the first place.
Removing the machine from AAD sets up a generic password that we don't know about.
Any ideas? How can I go about login into the computer?