Nanite foliage UE5.1 material crazyness

I have some foliage exported with datasmith from 3ds. If I enable nanite, the foliage seems to loose it’s material - in the picture the central hedge has nanite turned on, the one on the left and right has nanite OFF. Any suggestion? Thank you!!

Shouldn’t be masked materials supported by UE 5.1 ?

The flowers behind the fence are working nicely and are masked materials too… I can’t understand…