is Sure Gel fruit pectin? The same as used in jams?

Has anyone had experience using Morton’s Tender Quick on summer sausage? I have always used LEM packaged seasoning and cure and have never had an issue. I thought I’d try the TQ along with garlic powder, onion powder, black pepper and mustard seed. First try I used venison with 10% pork fat added. After slow smoking to 158 deg. I did a cold water bath (tap water temp) then placed the sausages on a rack to rest for 2 hours, then into the fridge. The fibrous casings would not turn loose of the meat. Just curious if anyone else has had this issue?