I think that might come from another member here, but what she describes is way too thick layers of material; when the layes of fabric is high enough to push the presser foot up to top postion like when it's lifted, some models release thread tension automatically, others aren't as affected, which can cause loops under the fabric, etc. It's not really affected by needle thickness or any slowness cause by resistance in needle punch and stitching; the mahcine stays perfectly timed for challenge like that. Thread tension on 27 and 28 is manual though, these models should take seam bumps rather well.
Last edited by Mickey2; 08-08-2018 at 12:14 PM.