Thunderbird on Debian creates folder .icedove

I am on a fresh installation of Debian, with Thunderbird as part of the Debian Cinnamon-Desktop. I just copied my .thunderbird-profile-folder from a previous installation over and then started Thunderbird. That's all working perfectly fine, accounts are loading, settings are in, all good. What's quirky is that there is now a .icedove folder. Of course Thunderbird complains about that at the next start, pointing to https://wiki.debian.org/Thunderbird#Adoption_of_User_Profiles. Which in this case isn't helpful. I delete the .icedove-folder, start Thunderbird and the .icedove-folder get's recreated again. At the next start Thunderbird is complaining about itself again. It could be "The Thunderbird package comes with a wrapper script in /usr/bin/thunderbird which will do the users profile adoption (if possible). It will be triggered automatically if a user is calling thunderbird from a CLI or via the desktop file." but shouldn't happen in the first place.