Thule jogging kit twisted?
One arm has an adjusting knob that forwards/retracts it, therefore correcting the trajectory deviation. See the blue Knob and the black plastic that it moves on the picture bellow.

No need to overadjust it, since small changes in how the wheel and/or arms are inserted will change the trajectory center the next time. Just make it good enough and correct small deviations by pushing the cart unevenly.