Yes, that can cause indeterminate steering — but not "torque steering." I've had those U-joints fail, though only the lower joint (not a fun job). Foe me, it has been a binding U-joint, which causes "notchy" steering (sorta stick-slip-stick-slip).

Torque steering occurs when you change the loading on the left versus the right side of the car. Toe-out will cause very noticable steering (as when you step on or release the gas). But often toe-out causes "squirrely" tracking—the car continues to weave left-right-left-right.

When you turn to the left, the weight is shifted to the right. The right tire is pointing right, and it steers the car right—and this shifts the weight to the left. The left tire is pointing left, and it steers the car left. So, back and forth, back and forth.

Also, worn rear suspension bushings can allow the differental to "wander" when you add or remove power, which permits "rear end steering."

Don Foster (near Cape Cod, MA)