The problem is created by over-twist in the yarn. Most yarn is created with more than one ply and those plies are twisted either clockwise or counterclockwise. Yarns with multiple plies include both twist directions. The original singles are usually S twists then the singles are plied together in the opposite direction.
The fibres push against each other creating a yarn which is referred to as being in balance. For balance, the twist in each strand of yarn needs to controlled by an equal twist in the opposite direction when the strands are plied together. Yarn which isn't balanced may become untwisted during the knitting. Knitters see this as splitty yarn. Our needle slips between the plies very easily.
You know your yarn has too much twist when it folds up on itself, twisting together in the section between the work and the ball of yarn. (Spinners know there is too much twist when the same folding up occurs when they pause during spinning.) When this happens, it helps to let the work dangle and to allow the yarn to untwist. Unfortunately, this is an extreme example, it isn't always this obvious of an over-twisting situation.
Yarns which have a tendency to bias are single ply, ribbon tapes and chenille in particular and all yarns have this potential depending on how they are created and handled afterwards. Often a yarn that twists when you are feeding it out of a centre pull ball will behave better if you work off of the outside of the ball instead. I've even used a yarn butler to eliminate the twisting.
KnitPicks carries a less expensive plastic version.
These accessories allow the yarn to flow off of the ball without adding more twist.
I'll have more to share on this topic soon.