so far after a rip down what i have found out is,
the Center Diff.Drive Pinion end (pic1)can get cockeyed in the housing part of center diff set(pic 2) when grub screwed all back up...
----Pic 1----
----Pic 2----
same with the first way shaft end going to the diff housing
not saying this can even be your problem
but i am sure of you check that housing over and make sure it proper..
when i ground mine down by the inter ridges of the housing ,it got worse.
weird it was like a small bur(smooth was just over the top of the inter ridge housing)
made it less of a gap within the housing
it would be great of that housing can be remade with more of a craftsmanship this way both shafts can fit in there without a gap causing it to move when grub screwed down...
mine just has a slight wobble but i ran it hard in 4 wheel drive and it held up
i still an going to re-rip it down and make it centered and fill the gap so when you grub screw it down it will not move...
it wouldn't be a problem
and i am sure that the Billet Clutch Bell Carrier is not tend to give up on more flex compared to the stock carrier that gives us leeway .....