Microsoft says the PrintNightmare Print Spooler vulnerability is working as designed and is effective against the known printer spooling exploits. Microsoft urges users to start applying the updates as soon as possible. Security researchers tagged the patches as incomplete after finding that the OOB security updates could be bypassed in specific scenarios. Microsoft has also issued an emergency fix to address printing issues affecting Zebra and Dymo receipt or label printers due to changes introduced in the June 2021 cumulative update preview with the recently released KB5003690, KB5004760, and KB5004945 updates.
Source: https://www.bleepingcomputer.com/news/security/microsoft-printnightmare-security-updates-work-start-patching/