Migrating project from GitHub looses reporters, assignees, commenters

Hi,

we have created a group with members having the same usernames as in GitHub and all people also connected their accounts to GitHub (now it shows “disconnect” in their account).

However after importing a project from GitHub, these people stay unassigned and all issues are assigned to me as I am the owner. I have no idea what I am doing wrong and where I can search for problems.

Thanks for any suggestion.