I picked up a 2nd Cull Shad in a different color after being impressed with my 1st one.  I usually use two 1/8 oz tungsten nail weights with the bait but only had one and a lead 1/8 oz nail weight. 

 

No biggie, right?  Wrong.  The bait ran all screwed up and wanted to turn on its side when retrieving.  I have heard of this issue but I hadn't encountered it until now.  I went to a single tungsten weight and all was well.  I think because the lead weight is so much longer and is inserted far deeper into the body that it upsets the center of mass.  The tungsten weights are far shorter and when inserted to only be flush with the body the weight is much more centered around the belly of the bait.  My long lead weight was in the front hole and the short tungsten was in the middle or last hole.  Just a cool observation that may help someone else with this issue.

I encountered this as well. I now use lead golf club tape on the treble shanks.