Hi Andy,
welcome to the sometimes confusing world of the Garmin XT2.
1st of all: I have very similar problems and I have already spent hours on working on a workflow for me with suing MRA and the XT2. I was using a Xt before, which works better due to the different "noon-concept" using Garmin Drive instead of the Explore world.
I also still struggle. as a quick fix I found out, that it works better if you use GPX 1.0 instead of 1.1.
Sounds strange, but improves the situation for me
Waiting for your screenshots, pictures and ready to exchange my experiences with the XT2.