I noticed something slightly odd yesterday when I was testing various pattern trajectories in the PMDG 737 NGX at EGPD Aberdeen. I informed ATC that I would be returning to the airport (remaining in the pattern), and started pushback. A Lufthansa A321 was also getting ready to depart, and the AI pilot was asked to wait for me. However, ATC reported that I was on the runway, not the taxiway. I was quite surprised, as I have never heard ATC make that mistake before. I wondered if it was a glitch, so I decided to start P3D again, and load the same scenario. The same incorrect announcement was made. Since I normally ask ATC for clearance to depart straight out (or in a particular direction), I decided to select one of these options when I conducted a third test. This time, ATC correctly informed the AI A321 pilot that I was on the taxiway.

I have not tested this with any other aircraft yet, so I have no idea if it is an issue with P3D, the aircraft, or the airport (UK2000 Aberdeen Xtreme), but I suspect that it is a P3D bug (and probably one that also exists in FSX).

Has anyone else noted this?

I take it you're referring to default ATC?

Yes, that is correct.

I can't say I've noticed this only because I don't have P3D at the moment, and even then, I don't use default ATC.