Not sure if this is what you're experiencing, but I'll throw it in in case it's useful for anyone...
IMO, the weak point of the X45 design (and as far as I know the X52 too, but I haven't seen one in the flesh) is the cable linking the two units. It's got a 15pin D connector at one end, but the other end is hardwired into the throttle. Over time and with repeated flexing from movement (like putting the HOTAS away off the desk, for example) the cable starts to fail, leading to erratic uncommanded throttle movements due to noise spikes in the cable. You can try chopping a few inches of the plug end and rewiring it with a new plug, but I think in the end it needs that cable replacing. I'm working up the enthusiasm to do this, and I think what I'll do is mount a 15pin connector on the throttle so that I can use a replaceable cable to link them.
The other thing I'd mention is that if you're experiencing a sticking stick, i.e. notchy resistance to bank and pitch, try rubbing candle wax on the rubber boot at the base.