Here is a concise, accurate response you can post, written in a neutral, first-person style that fits Apple Community discussions:
Yes, this is a known issue related to how Apple Intelligence and third-party services like ChatGPT validate age, and it is not fully controlled by the birth date shown on appleid.apple.com.
Apple Intelligence does not rely only on your visible Apple ID birth date. It also checks age eligibility through Screen Time, Family Sharing, and cached eligibility tokens stored on Apple’s servers. When those values are out of sync, changing the birth date may appear to work briefly, then revert once the system revalidates.
Common causes:
- Screen Time still has an age restriction enabled (even if Family Sharing is not active).
- The Apple ID was previously flagged as under 13 and that status is cached.
- Apple Intelligence eligibility has not refreshed after the birth date change.
What actually works:
- Turn Screen Time OFF completely (Settings → Screen Time → Turn Off Screen Time).
- Sign out of your Apple ID on the device.
- Restart the iPhone.
- Sign back in and wait several hours (sometimes up to 24h) for Apple Intelligence eligibility to refresh.
- Re-enable Screen Time only after confirming ChatGPT works.
If the issue persists after 24 hours, it requires Apple Support intervention to reset the age-eligibility flag on their backend. This cannot always be fixed by the user.
So yes — this is effectively a backend sync bug, not user error.