I agree with Dunster, the picture you are showing is a tension problem not a thread problem. I looked it up on line and it is indeed a trilobal polyester thread but nothing on line told me what weight it was. Usually (but not always) trilobal polyester embroidery threads are a 40 wt. I use trilobal poly thread meant for embroidery in my LA all the time and don't have any issues. I think you need to tweak your tension considerably. Inspect your bobbin case thoroughly, if you normally use cotton you could have a blob of lint stuck in the tension spring of your bobbin.
As Dunster said, if what you posted is the back of the quilt the bobbin tension is much tighter than the top right now. So, once you check your bobbin tension spring to ensure it is free of lint, you need to either loosen your bobbin or tighten your top tension. But be forewarned, not all trilobal poly's are created equal. Some are much weaker than others so if you tighten the top and then start experiencing breakage you need to go the other way and loosen the bobbin so you can accomadate the thread running through the top running at a looser tension setting. Here is a diagram that should help you. https://www.superiorthreads.com/education/how-tension-works
Last edited by feline fanatic; 04-20-2019 at 10:51 AM.