Bisecting between v4.10 and v4.11 resulted in finding that this was caused by the following commit: [ef65aaede23f75977af56a8c330bb9be8c6e125c] smb2: Enforce sec= mount option
Reverting it on top of v4.11 makes it go away.
Looking more into it.
Bisecting between v4.10 and v4.11 resulted in finding that this was caused by the following commit: 977af56a8c330bb 9be8c6e125c] smb2: Enforce sec= mount option
[ef65aaede23f75
Reverting it on top of v4.11 makes it go away.
Looking more into it.