Thanks @szymon_dybczak ! I confirm that's a permission issue and assigning "CAN MANAGE" solves it.

I still find it not really intuitive, since the goal is to use a shared cluster (with ML runtime) for development purposes. I mean, it would make sense when following the recommended approach of storing your code in "/Workspace/Groups/<groupName>", but for the integration with Git Folders it really adds some complexity.

The whole team assigned to the group will need to grant access to their Git Folders 😅