Confirm that the aircraft was on autopilot, and also that your SOPs prohibit the uses of locking onto a climb rate.
I'm assuming that the PF reacted to the attitude fairly briskly. I would feel decidedly uncomfortable sitting in a 72 at that weight, while significantly below V2. I have to say, that my first thought would have had more to do with getting rid of that pitch attitude following a sudden drop in airspeed.
You may find that the slight fluctuations in the engine parameters were due to the vertical component of the airflow at the engine intakes. But I don't know.
A drop of 25 knots, is in itself, not really very significant met-wise, things like this are going to happen quite often over the years.