Has anyone else experienced the Topeak MTX DXP bag getting stuck in the rack? I've got the MTX DXP luggage bag from Topeak.
Their suggested rack is the MTX Dual Side Frame, but I have the Explorer Tubular rack (image on site is reversed with the spring version).

Since it's listed as compatible, I'd expect that it would mount smoothly, until the latch catches, but instead it's really sticking on loading it in, and it near impossible at times to remove.

Is this something anyone else has experienced?

For today, I'm going to try applying some lubricant to the track, to see if that helps at all, but it seems like it's a really tight fit.
The Topeak rack systems all fit pretty well, I have sold a few in my time and not encountered any problems. I don't believe there are any bolts for fitting that could be potentially put in wrong to compromise the rail/fit, but the fit on them has to be snug because you would not want it rattling away. You do have a compatible bag/rack combo b.t.w.

I am not sure you will find anyone on here able to confirm the same problems you are having, and these things are subjective anyway - some people just put up with a problem like this. What I suggest is that you try your bag on a different rack. You can go into a bike shop for this or you can scout around the bike racks and see if there is another rack you can borrow. Topeak are usually very good on warranty issues, so if you do find a problem then it will most likely be sorted by them.