Missing support interface layers

Hi,

I am trying to support a large bridge printed with filament that doesn´t bridge well. The weird thing is, i cant get slic3r to generate the interface layers. The only thing with correct support and interface actually is a hole. Makes no sense to me at all. "Don´t suppor bridges" is deactivated, I also played around with the overhang threshold but no luck. When I print the part, the support structure falls right off, despite a very low contact z-distance.

What am I missing here?

Oh, tested on 1.39.1 and 1.41.0-beta PE, Win10

Update: I found the culprit!
I think it has something to do with the Layer Height Limits in the Printer Settings tab and the contact Z distance of 0.05 I was using. Changing the distance to 0.1 resolved the issue.

It would be nice if there was a warning somewhere that the two settings affect each other or at least some hint that the support couldn´t be generated correctly. It messed up at least two long prints until I found out what was going on.