I have to admit my ignorance:
In the T7, if the FMC is in HDG mode, does that mean it follows course over ground, true course or magnetic course ? And likewise if you are e.g. in Phuket and set e.g. Ushuahia as next waypoint, would it automatically follow a great circle ?
Knowing the answers to these question and knowing all of the "ping arcs" may give some clues as to how the AP was set on that last journey.