Spells: Divine Purpose causes mana total to fail to properly update after going oom.

[asmoeq]

Had a bit of trouble getting this to reproduce, but I have it down to 100% repro at the moment.

Bug: If the mana drain from Divine Purpose takes you to 0 mana while standing, sitting and meditating does not return mana or properly update your mana pool until after you take off or cancel the Divine Purpose buff.

Repro steps:
1. On a Paladin that has access to the Divine Purpose spell (lv. 39), cast Divine Purpose.
2. Get yourself relatively low on mana (20 mana or so) by casting miscellaneous spells. Alternatively, just stand and let Divine Purpose drain your mana until you are sufficiently low on mana.
3. Wait until the Divine Purpose mana drain effect takes you close to or at 0 mana.
4. Note how your total mana then seems to fluctuate between 2/4 mana total, and mana drain does not continue.
5. At this point, sit and meditate for some time.
6. Note how your mana does not increase despite sitting and meditating.
7. After a few minutes, stand up and attempt to cast spells.
8. Note how you are given the Insufficient Mana message.
9. Cancel the Divine Purpose buff.
10. Wait for the next tick.

RESULT:
1. The correct mana total is only updated after the Divine Purpose buff is cancelled. The next tick will update your mana back to the appropriate total. However, the total is also incorrect, as it seems that the mana drain from Divine Purpose has taken you into negative mana and whatever you gained back from meditating has to first zero out before going positive.

Lots of stuff going on here, I'd be happy to provide more information and video to show you the bug in action if necessary.