Is there an intermediate shaft bearing on that axle? Is there a snap ring that hold the axle into the differential case?
CV joints, like plunge joints, have the capacity to move in and out along the axle's center line. If the inner joint is supposed to be locked in place with a snap ring and it's not, the knocking you heard is not a surprise.
If this axle has an intermediate shaft bearing and it's not torqued properly, the axle will rotate out of axis.