Spell: Few Lesser Planar Conjuration bugs

[Frumple]

1. Uses held mana. The description makes no mention of this whatsoever.
2. Being unable to cast the spell (because of, say, not being beside a summoning circle) will consume held mana anyway. That should probably not happen.
3. The summon creature disappears after a few dozen turns, instead of lasting a full day.

Attached is a character fairly deep in the dungeon, with the spell learned and near a conjuration circle. Simply step beside the circle and cast, then search a few times to observe the entirely too limited duration.