Thanks for the input, Nathan. I recently logged in as non admin and towed a train of vehicles 5k without a hitch. They were a hatchback, attached to a mission armed off-road with a crate and my personal atv in the back all towed by a mission ural. The bug seems to affect some players, but not others, and I do believe that it is indeed desync that is snapping the ropes. What is causing the desync is the issue.
One thing to make sure of, if you aren't already, is that none of the tow ropes used are for any vehicle that is loaded onto another. It is easy to get the ropes, of say, an atv in the back of an offroad by accident and attach them to a towed car. You do this, it isn't going to end well. Always try to use the largest vehicle to tow with, and if possible, carry the most load in the driven vehicle and make sure the only tow ropes used are from vehicles that are actually on the ground.
Edit: I finally hadit happen to me a couple of times. I was towing a crippled armed offroad with an atv (both pinned vehicles) and it detached twice on me. First time i just picked up the ropes and re-attached and it came off soon again. Second time i stowed the ropes and re-deployed and continued without an issue. Still researching. but I haven't found any fixes yet.
This is a very capable, but apparently somewhat temperamental tow system. Its the only one that I know of that will let you tow multiple vehicles legitimately but compensates for vehicle weight and limits exploits. It worked flawlessly on the old Extreme server and I really hope to get the bugs out now. thanks for your patience.