Hello!
I changed a bit of code on version 1.6.1 to prevent this behavior when background images are not correctly set... I tested this a bit, but something may have slipped unnoticed. Are you using version 1.6.1, right?
If yes, can you setup a test project for me with the issue present?
You can send me a download link here, or send me a private message on facebook or the official RM forums.
With that I can check exactly how your parameters are set, reproduce the issue and debug to discover what is going on.