Help Zero-g

[josemendez]

Interesting, thanks for taking the time to look into that.
I notice two immediate differences. I've set the solver gravity to zero, and I have a rigidbody on each end, with the last particle having a pin constraint to the rigidbody. 

I don't get the opportunity to work on this every day, but the next time I get the chance I'll try an isolated scene, and if it still behaves the same, send it to you. Thanks

Make sure the last particle (the one that's pinned to the rigidbody) isn't intersecting the rigid body in its rest state.

If it is, that's the source of your problem, as the collision constraints are trying to keep the particle out of the rigidbody, but the pin constraint is pushing the particle back into the rigidbody. This is what is known as "constraint fighting", it can create an energy feedback loop that keeps your rope twisting in an attempt to free itself from the collision against the rigidbody. In that case simply set that last particle "phase" value the same as the rigidbody. Bodies/particles in the same phase do not collide with each other.