Seems to also be the case with the mighty and tremendous blow barbarian abilities.

The issue seems to be that the energy cost penalty is applied a turn too late. If you use mighty blow against a monster, it gets one attack. If you use a normal attack against the monster the next turn, it gets 2-3 attacks. The same applies to moving and triggering auto-pickup (1 attack the turn you move and pick up, 2 attacks the turn after), and to book-casting (1 attack the turn you book-cast, 3 attacks the turn after).

Interesting! But I think the bookcasting specifically got fixed, I havnt tested mighty blow in the new version though.

None of the things mentioned here have been fixed in r72.

There's also a bug where the last energy cost display is set to 1000 when you perform actions that don't take any time (adjusting tactics, looking at inventory, etc): 4618. It turns out this isn't just a display bug; since you pay energy costs a turn late, you can use this to set the last energy cost to 1000 and avoid ever paying for higher energy cost actions.

Whoa damn. You are a bug wizard!

Appears to be fixed in 2.3.1. While the issue with non-actions changing last energy persists, it is now only a display issue.

Setting this to fixed in 2.3.3 so that it shows up in some changelog.