I'm not sure if it's changing shape or just not right from the beginning.
I noticed the same thing, didn't think to much of it at the time, the rollers hanging up a bit when I took out the stock helix before the first trip. I put MDS weights and a 45 degree helix on before the sled ever touched the hills. Worked great the first two trips. Then before our third trip, I put the stock 48 helix back on. I just wanted to see if I could notice a difference and damn was that a mistake. It was pretty clear it was getting hung up. The sled would backshift ok at times and then at other times it would not backshift at all. Was not consist at all, fine one second then crap the next. That night I put the 45 degree helix back on in the hotel room, the next two days were awesome. Adjusted the weights a bit to pull the correct RPMs and the sled ripped. But wow was day 1 miserable. I was super confusing why a 3 degree change in helix would have that much of an effect. But after seeing this post I'm seeing some clarity. I'm certain mine was never right from the get go. Have about 270 miles on the Dalton 45 helix now and it's working great. I was running a different 45 degree helix on the 16 and after maybe 400 miles the inner orange bushing (same as the stock bushing) was trashed.