Experts suggest that the timeline for Gmail fully enforcing a DMARC quarantine policy remains uncertain. While initial deadlines, such as February 2024, were set for compliance with authentication requirements, a hard date for quarantine implementation is not definitively known. Google provides limited information regarding updates, making it difficult to predict the exact timing. The subdomain policy is currently set to quarantine, but broader enforcement hinges on factors like reducing ESP-sent mail using Gmail addresses. Proactive email authentication and reputation management are crucial, along with ongoing monitoring.