I know its rather mundane, but first off check if your stuff is actually Bandai, not some bootleg. NOw, assuming that its the legit stuff....
Firstly, the weapons. Specifically, the pirate beam pistol and awesome-looking pirate beam cutlass. Does anyone else have any problems getting the X-1 to freaking hold them? At all? With mine, the cutlass absolutely refuses to stay in the hand, and falls out no matter what I do. The peg in the hand that the hilt connects to is far too small, and the niche in the hilt is far too shallow, so there's no connection at all, and with its weight, it simply falls out if I try to use the fingers to support it. And the beam pistol will only fit at extremely awkward angles that, frankly, would be impossible to fire a gun with.
It is a problem with alot of MGs (or more accurately, those with moveable digits.) Had the similar problem with the MG F91 (which would be using alot of Xbone's ABS) and WZC, which did not even have the peg, and usually primer'n'paint solves the problem. if not, a little bit of Elmer's glue or a small piece of tissue paper always works wonders.
Secondly, is Bandai sticking with this ridiculous no-polycap construction? Because it seems extremely rickety. With all the past Gunpla I bought, they were almost always very sturdy and flexible, with the polycaps basically working miracles in producing highly poseable suits that stayed together in one piece. This Crossbone, on the other hand, isn't quite so flexible in places like the base of the legs and the elbows without pieces popping out, and whole limbs (and skirt pieces) pop off without much provocation purely because of how weakly this no-polycap system holds them in there. Please tell me Bandai's realized this was a bad idea, or else I think I might be done with Gunpla, and will have to move on to something else. Like HCM Pros.
Since once again Xbone's frame is identical to the F91's I'll use my F91 experience and say no, I had no such problems. In fact, it's quite the opposite, I find this no-polycap gimmick a much sturdier
option. And if you go through dalong.net's MG pictorials you'll see that the trend is lowering polycap amount on MGs (this started on the MG WZC and Freedom) to nothing/almost nothing. The other new releases like Strike Freedom and Hi-Nu probably has less polycaps than a 1/100 Wing kit.
Your experience piqued mine though, as I have 3 (count 3) unbuilt, boxed Crossbone MGs.