Hi s7r83dg3, it's pretty hard to tell what you're running into without actually seeing the model.

Could you please post a 3DM file with your cube and triangle in it so I can see more exactly what you are talking about?

You may be running into "autoplace" mode kicking in, or you may want to adjust the Twist: option in Sweep.

Here for example I've done 4 sweeps of a triangle around a cube and I don't see any issues:




But you may have placed the profile in a different spot than I did, or have something else different.

- Michael