My husband and I just purchased a 2012 CX 9, and I am finding the same problem with the headrest as your neighbor, except I find it uncomfortable all the time, not just on long trips. My husband doesn't seem to notice a problem,he is 6'8" and I think taller than the headrest, but I am only 5'7" and it is really bothersome.
I am not happy that I didn't notice this while test driving (maybe b/c we didn't get a chance to test drive without dealer sitting in passenger seat, I sat in back and didn't sit in passenger seat...which is completely my bad and I am BS about it). Now I am stuck with the car, which seems to be nice so far, except for the passenger seat (along with the headrest, the entire seat is uncomfortable... it tilts forward and you feel like you are sliding off).
Help!
Any tips/fixes would be greatly appreciated! Thanks