Groupfolders update 5.0.5 > 6.0.1 finishes but does not work

I’ve today updated my NC instance from 17.0.3 > 18.0.1
Afterwards some apps, including Group Folders weren’t updated and marked as "not official

The weird thing is, that I can choose to update these apps (via the GUI and as well in OCC) and I receive a success notification, but when I choose occ update:check it looks like before the update:

occ $ app:update --all
groupfolders new version available: 6.0.1
groupfolders updated
fulltextsearch_elasticsearch new version available: 1.5.0
fulltextsearch_elasticsearch updated
calendar new version available: 2.0.2calendar updatedimpersonate new version available: 1.5.0
impersonate updatedterms_of_service new version available: 1.4.0
terms_of_service updatedmail new version available: 1.1.3
mail updated

occ $ update:check
Update for calendar to version 2.0.2 is available.
Update for fulltextsearch_elasticsearch to version 1.5.0 is available.
Update for groupfolders to version 6.0.1 is available.
Update for impersonate to version 1.5.0 is available.
4 updates available

Any ideas on this?

Just had a look in the logs and found hundreds of error messages like this:
copy(/.../nextcloud/apps/groupfolders/groupfolders/vendor/phpspec/prophecy/src/Prophecy/Promise/PromiseInterface.php): failed to open stream: No such file or directory at /.../nextcloud/lib/private/legacy/helper.php#148

Hey Jooohannes. I see that your groupfolders app is nested again in groupfolders

/…/nextcloud/apps**/groupfolders/groupfolders**

This could be the issue, since the updater could not find the correct path

Haydar