False Positive, but not completely False Positive.
PaloAlto has been having this trouble with UaCredService for over 10 years because PaloAlto uses Mimikitaz code within UaCredService. More specifically, UaCredService takes the domain user/password and checks it over the internet. UaCredService performs credentials verification when the credential detection feature is enabled. When a corporate (usually a domain) user uses their credentials to access some resource, their credentials are sent to the UaCredService which, in turn, checks the user's credentials over a network with a connected Credential Verification or Authentication Service (not a PaloAlto product or service). This entire process mimics Mimikatz and UaCredService uses Mimikatz code.
Submit ticket to PaloAlto or search available PaloAlto support forums for confirmation of further details.