linux mint 18 mintupdate launcher still shows kernel update level 5even if level 5 not activated

[xcape77]

I freshly installed LinuxMint 18 64bit Cinnamon. then I made update with "sudo apt update && sudo apt dist-upgrade". Then I rebooted the system. Then I was wondering why update manager still shows an update available (linux-kernel 4.4.0.-38-57, level 5).
So I set level 5 to inactive, both, secure and visible.
Then I freshed up the view up. Waiting a few days. Made other system updates.
But update-manager still shows linux-kernel (level 5) as an update.

[xcape77 (xcape77)]

same thing when I disable level 4, also level 4 updates still shown