First, your best source of info is Nolting or your dealer. I am sure they can walk you through your issue. Your first course of action is to call them from a phone where you can easily access your machine while talking to them so they can walk you trhough step by step what to try.
Some things to expect...
Does your take up bar need to be adjusted for the higher loft batting?
Another thing, perhaps your stitch regulator encoders need a cleaning. I take a q-tip with rubbing alcohol and gently clean the encoder wheel that rides on the rails, make sure you turn it to clean all sides and make sure you get both the front to back encoder and the side to side.