if the half moon is broken, then it's possible that the front cam cover is not on flat, and you've probably bent the CAS axle also.

Have you replaced the cam belt? are you sure the backing plate and bezels that locate it are installed properly before tightening down the bolts that hold the backing plate to the block?
Because if they aren't, when you put the front timing belt cover on, it goes on crooked.

The CAS should slide into place pretty smoothly. If any 'man handling' is required, you have done something wrong.

Check it out!

I've seen camshafts, and CAS shafts snapped from the issue I've just described.