There seems to be a bug that can set your Magicka flipping back and forth from its actual value, to a very large negative value. It looks like it might be related to talking to the Mage's Guild trainer. Not sure how to fix it or what, specifically, might be causing it.
* some residual value somewhere that's convinced that my character still has "NoSpellPointRegen = true"?
* Very unlikely to be multiple magicka regeneration scripts. Given the number of reloads and saves, my magicka would be regenerating very rapidly right now, and it still seems to be moving at the "per 30 seconds" value
Anyway, if anyone has any more info, please post it.
Edit: Resting or a full reload seems to fix it.
Previous experience tells me it's very easy to misunderstand the tone, intent, or meaning of what I've posted. If you have questions, ask.