Yes this type of issue is essential a known bug although your specific case may differ slightly. Sorry for the confusion.
It is not currently possible to allow someone to view/edit on CircleCI that does not have the appropriate permissions on your vcs-provider. (E.g., even open source on CircleCI needs the project to be open source on your vcs-provider).
Our current permissions model is effectively 1:1 to your respective vcs-provider so our Invite Teammates flow is just for convenience sake - the list is only meant to show users that have access on your vcs-p that aren’t yet signed up for CircleCI.
If the user has access on your vcs-provider, they should be able to automatically view on CircleCI.
We’re working to separate our permission model to give users more granular controls now!