Some plants lack shadow at runtime

Hi, I have set plants with the foliage actor. Strangely enough, not all of them show a shadow at runtime. In editor all shadows are there. It is always the same plant. Settings of Mesh in FoliageActor: “cast shadow true”, “cast dynamic shadow true”, light map resolution 32", “affect distance field lighting true”.


Image: on the right shadows, on the left no shadows.

Any idea what this could be?
Thanks in advance

Solved. An upgrade from UE 4.26 to UE 4.27 fixed it.