Decided to try Pro Armor Tethers this year as well on two sleds, mine and a buddy's, unfortunately both had issues......................
After the install on my buddy's he had the same issue as you, he filed a spot where he thought it was catching and hanging up but it still didn't work quite right. He ended up calling Pro Armor and getting a complete new tether.
After installing mine, and looking all cool, I started the sled, grabbed the tether line and gave a quick pull and presto the sled quit just like it was suppose to. But.........after grabbing the end clip to re-insert and give it another test, I realized there would be no second test. The damn clip broke on the first test!!!!!
I know it sucks azz but.......Pro Armor was cool and sent me a brand new tether cord replacement and apologized for the inconvenience. So hopefully mine was an isolated incident but if not I did order a second tether cord / clip combo to keep in the sled as a spare.
I've heard nothing but good on Pro Armor and their products so, hopefully your issue as well as ours are very few and far between!!!!