OK, since we KNOW it's index housing, we need to tweak my extruding theory to match the spiral pattern the OP is getting.

The housing either isn't cut square or it's partly extruding through the ferrule, so some strands are loaded and others unloaded. Since the strands spiral, the unbalanced loading causes the corkscrew effect the OP is getting.

The fix involves 2 elements.

1- after cutting, touch up the end with a file or a quick end on touch on a bench grinder. You want a nice square end, not anything cut at an angle.
2- use proper fitting flat bottomed ferrules made for index housing. These have structural bottoms that won't deform or allow partial extruding of the strands. The best index ferrules have brass or steel discs with a upward pointing cone pressed into the bottom. The slight cone forces the strands out away from the hole, ensuring that they cannot extrude through.