I can see that being a problem. I'll release v2.5.2 shortly with this changed alongside a change to importers I forgot to include.
Once v2.5.2 is installed, you can run the "Rebuild group memberships" action from the Maintenance page to update everyone's group membership records.
They are not coming from a URL, they are requested from CloudWatch nightly during the daily stats gathering, if you have set up an API key in the settings.