The climb tq limit is something that has only been introduced in the last 8 years and it seems a lot of old courses still don't teach anything about it and some instructors/check and trainers still choose to ignore it.
Yes, seems that way. I've flown the first generation vans quite a bit, and never recall coming across this limitation in the original 80's operating handbook in the aircraft.
I've just spent some time looking through a 2004 POH and cannot find a reference to climb torque limitation there either, just Ng and ITT.
Did something suddenly change in the engine in the last 8 years?