UPDATE
I asked the user to logoff and logon back again to see if the issue persisted.
This fixed it despite the fact she logged on to the exact same server.
Currently I am comparing the mentioned logfiles of this user captured during her sessions while having the AdobeID issue and not.
When I parse the oobelib files via diffchecker.com I see quite some differences regarding license validation.
Please let me know if you are interested to review them.
Regards,
Raymond