thx for the help guys, I found the error. As you can see on this pic, the soft playable area is bigger on the north side of the map than on the south side(minimap), which makes you not able to see the unplayble area unless you change the camera angle.
With the soft unplayable area set to 32m you can slightly see the unplayable area, which im not used to from relic maps, so it cought my eye

(No offence to onclesam, awesome tutorials!)