Well, unless the piston/cylinder is out of whack either because of barrel timing or the splines/keys/whatever that position the cylinder on the barrel is out of whack (could be, don't know), you know that one or both of them has something going on.FWIW, the op rod does not appear to be bent and the guide does not appear misaligned).
It may be as simple as whacking the operating rod guide over a little bit with a mallet, if it hasn't already been loctited or otherwise secured. You can look down the line of the operating rod spring guide base to the cylinder and see how the guide lines up to see if you're going to be whacking it towards or out of center. If you're knocking it towards center, and it frees up your movement, maybe pull it apart, loctite it in place with the red, get that center pin through, let it set, and then go enjoy your rifle.
If the operating rod guide won't budge, you might need some heat to get it free, though I've never done that, and don't know if you have to worry about screwing up anything with too much heat, so I would consult further with somebody experienced with it, and if I didn't feel comfortable doing it, consider sending it to Bula, getting Jeff's attention that it's coming before you send it.