Comment 2 for bug 1952811

This message is only returned if we detect the model UUID in the models collection.

I have a suspicion about redirects here.
Is it possible that the target controller has models with the CMRs to the *migrating* model?

See this patch:
https://github.com/juju/juju/pull/11025

I wonder if there is a possibility that we followed a redirect to *source* controller, which told us that the model is present.