Druid mana bug

I’ve had random occurrences with my druid where when I am in a moonkin or Flight Form I’d go from 1% mana to 100% mana. I figured it’d be worth mentioning, I do not know how it happens or why it happens but I just didn’t want to let this become something that someone can bug abuse.

This is a bug on Wrath Classic at this moment that I have discovered while questing.