if using a walking foot- you need the feed dogs up-working- if you are using a free motion (hopping foot) you have the feed dogs down (not working)
prehaps you could just choose a different decorative stitch that does not conflict with your fabrics. machines with decorative stitches usually have many to choose from- put together a (practice sandwich) with some of the fabric you plan to use- and try out a few different stitches on it- then decide which looks best to you. the one you have just conflicts.