Some layers from .ai-file is imported into a random layer

I want to import all the layers as boundary curves from an .ai-file. They import fine into the program. At least some of the layers. A random amount of layers are put in a random existing layer (called “Plane” in the screenshot). It does not matter where “Plane” is in the layer order, the imported layers get in there somehow. The problem is that I can’t have those layers mix up in Plane because I can’t separate them afterwards, it is too many curves.

Hi Eliash - I’d have to see an example file- post here or send to, with a link back here in your comments. The simpler the better, so long as it shows what you are asking about.