Copy WHENEXISTS not working for collections

It seems, when copying a file to a collection, the copy command does not look at the WHENEXISTS or FORCE switch.

This is the command I run:
Copy WHENEXISTS=skip FORCE CREATEFOLDER="coll://'MyCol" COPYTOCOLL=member TO "coll://'MyCol"

I cannot get around that popup: "The item is already in the collection".
Is there a another thing I could try (despite checking for existence myself before copying)?

Thx! o)

Ok, so testing if there is a file in that specific collection already works with: