I use the Crayola Ultra Clean markers. Washable markers can on very rare occasion leave a bit of color on the quilt.
As far as the Color Catcher, it probably is from the markers. I usually soak my quilt in the bathtub first to remove most of the color -- sometimes with a bit of Tide Free. When it seems good, I toss it in the wash on the gentle cycle with cold water. Sometimes I use a Color Catcher, sometimes not. It mostly is just for my own peace of mind as I seem to be fine either way. The soap will do the work of removing the marker, but yes, my Color Catchers do come out colored if I put my quilt in the wash with the marker on it.