Hello Rob Fink,
Thank you for posting in Microsoft Community forum.
If we add ADDS role on one server and promote this server as one Domain Controller, there should be Active Directory Web Service.
If two of the domain controllers don't ADWS in services work fine? If so, why you need this ADWS service in services?
If you must need this service, you can back up one of the domain controllers don't ADWS in services, and uninstall the ADDS role and reinstall ADDS role, after that check if you have ADWS service.
I hope the information above is helpful.
If you have any question or concern, please feel free to let us know.
Best Regards,
Daisy Zhou