I have the same problem with my x0xb0x and I'm NOT using software in my chain at all.
I get a delayed start (1 tick I think) from my octatrack - and/or from my mpc. The x0x is one tick behind which isn't super obvious at a normal (120-125sh) bpm.. but it is noticable, and when I chain drum machines off it it's VERY apparent. Example setup: octatrack master, midi clock out to x0xb0x, midi thru to a drum module, and din sync out of the x0x to tr808. The drum hits that are midi notes sent to the module are right on time with the octatrack, the x0x is slightly late, an the 808 is slightly late.. overlapping kick drums sound phasey at 130, flammed at 120, and a whole beat behind at much slower tempos.
I have seen posts all over the forum about this and people often blame software.. but something is wrong with the midi start receieve on the x0x. I've tried many different firmware - same problem on all of them. Currently I'm on the latest sokkos.
I'm super frustrated here - anyone have any knowledge on this?