Never had a problem
I've used the cargo cover about 80% of the time for over a year and I have never had anything like your problem. You might check to make sure it is seated and oriented correctly because the spring loading will hold it in place even if it's rotated. The slot has to be on top facing aft with the logo showing on the top of the cover. If it is seated correctly, then I would say you have a defective one and you should see your dealer about a replacement because they should not do what you have described.
Meep Meep
I've used the cargo cover about 80% of the time for over a year and I have never had anything like your problem. You might check to make sure it is seated and oriented correctly because the spring loading will hold it in place even if it's rotated. The slot has to be on top facing aft with the logo showing on the top of the cover. If it is seated correctly, then I would say you have a defective one and you should see your dealer about a replacement because they should not do what you have described.
Meep Meep