As some mentioned, this indicates that the aircraft has moved during alignment. If someone struggles finding the issue, check your axis assignments for pilot and WSO. In my case I forgot to invert the thrust axis for the WSO, so I ran into this issue the moment I switched from pilot to WSO to engage TEWS and TGP to STBY. The fact, that you cannot hear the engine (thanks ECS :-))and that the wheel chocks were in place, prevented me from recognizing I am on MIL power for a short time.