I have an S5 T2. I thought I could hear a clicking sound coming from the CAS so I pulled it and I found small marks on the gear. But, I'm not sure if the marks are just normal of if there is a problem.
You can see the marks on the gear in this pic. The marks are not nicks, they are just friction marks like where the two gears mesh.

 

On closer examination, there are small slivers of metal on some of the cogs of the CAS gear. I don't see any damaged to the distributor position gear but something must be out of alignment or bent.

 

If the wrong spacer was used thus making the end play incorrect, would this cause the distributor drive gear to be incorrectly aligned with the CAS gear.

 

the spacer just sets the end play on the cas and should have nothing to do with how the two gears mesh .
Check down through the cas hole and make sure the gear is tight and straight .
Does the shaft fit tight in the cas ?
If there is slivers of metal then there is a problem somewhere in there , turn the engine over slow and check down through the hole .
the bits might have nothing to do with the cas and coming from somewhere else have a good look something must be loose .

 

I pulled the front cover. The distributor drive gear appears undamaged. Nothing seems to be out of place. The correct number of spacers and bearings are present.

I guess I could swap out the distributor drive gear and the CAS and see if the gears mesh properly.