It cleans up at the end of the turn (before you are charged for that mana).  We dont want to recalculate global resources each time a unit dies, but it does create a case where you can see the maintenance in there until the next turn.

Im unable to reproduce any issue where it stays around outside of that short time frame.

Hi Derek, I found the problem.  Like you said, the fire elemental stays in your enchantments until the next turn.  If your fire elemental dies, and you save the game in that same turn just after the battle, reload the save game, he stays in your enchantments forever.

No worries

Bonus points for Ausland! Does he get a pony, too?

Might as well ask for a hippogriff... adds flying and looks cooler when you ride it.

Or a pegasus at the very least

Please ensure that all variables which update upon the crossing of a turn are accounted for in saved games.  An oversight in a "multi-threaded" process of this nature will create bugs as the software evolves.