So, I am using the same position in a CZML file, sometimes as part of a time-dynamic position property, and other times a stationary, constant property. When I use the stationary constant property, the entity renders in the expected location (near the AZ/NM border), but when the same position, and nearby positions, are used, the entity appears in a radically different position, which seems to be different depending on the time of day. This happens whether I use cartographic or cartesian coordinates. Why does this happen? Is there some way that I can account for this?
I figured out what I was doing wrong - I was using the wrong referenceframe (inertial) for the time-dynamic positions, and the right one for the stationary position.