as the title says; is this normal behaviour, or maybe just specific to my model?
When i de-skin it in blender blendshapes do import. But only either one or the other, skinning or blendshapes.
I think I may have discovered the issue. Do you have modifiers on your model? Subdivision Surface, Mirror, that sort of thing? I was having this issue with one of my models, and it wasn’t until I actually applied the Subdivision Surface to the model that it would export to FBX with armature and blend shapes intact.