Gmail connector fails with "requires additional permissions" even after reconnecting/adjusting OAuth scopes

The Gmail MCP connector (mcp__.../create_label and likely other write tools) consistently
returns:

"This connector requires additional permissions. The user needs to reconnect it with the
appropriate access."

Steps taken to try to resolve, none of which fixed it:

1. Adjusted connector permissions/scopes in settings
2. Clicked "Use" on the connector re-auth prompt
3. Repeated attempts by the agent after each step

Expected: after granting write scopes (e.g. gmail.labels, gmail.modify) via the connector UI,
write operations like create_label should succeed.
Actual: the same permissions error persists across multiple reconnect attempts, with no clear
UI indication of which specific scope is missing or whether reconnection actually took effect.

This makes it unclear to end users whether the reconnect flow is broken, silently not applying
new scopes, or whether there's a caching/session issue on the backend not picking up updated
grants.

Requesting: clearer error messaging (which scope is missing) and/or a fix to ensure updated
connector scopes take effect without needing a full disconnect/reconnect cycle (or confirmation
that a full disconnect is in fact required, since that isn't currently indicated anywhere).