I missed the last 13 years, but most of the 4 before that too. So I'm not sure whether this is a bug or has to do with various changes to critter, 3.0, so forth.

I've noticed the following at the moment:

bug analyze maneuvers (barbarian) seem to move expertise with lesser dusky-scaled basilisks but not the more difficult Maelshevyn Shadow Beasts.

Appraisal seems to move red bear orc raiders lesser than aforementioned basilisks, which are more powerful. In fact, it almost seems like appraising the much lower hulking black barghests teaches faster than basilisks.

Meanwhile, shadow beasts, which aren't all that much tougher than basilisks, teach appraisal much better. Something like 4/34 or 5/34 each time.