In the vanilla game, when an absorb spell, say, Absorb Health, is reflected, it has you absorb health from yourself, so no change and nothing lost. The MCP has an exceptionally annoying "fix" for this behavior toggled on by default and located under bug fixes. The "fix" makes it so that when an absorb spell is reflected, the target absorbs from you. The result is that one of the best outs for mages trying to not get annihilated by anything with reflect becomes one of the most painful ways to quickly die while healing your enemy.

I cannot see how the vanilla behavior constitutes a bug. After all, if the portion of the spell targeting your opponent gets bounced back to you, how does that necessarily mean that the portion that only affected the caster (being healed by the health lost) gets swapped to the enemy? This seems to me to be a game balance alteration, and the MCP description also mentions that the vanilla behavior "feels too safe for a game mechanic" as the reason for the change.
Unfortunately, OpenMW copies this behavior. Not only that, but here, it isn't optional, we can't toggle the "fix" off. The result is that enemies with reflect render pure mages almost unusable at anything below godly levels on OpenMW, and the only solution is to mod the enemies so they don't have reflect effects. Can someone please alleviate the pain here? Even making it alterable through editing config files would be lovely.
P.S. Also, please make the drain int exploit work again, even if we need a cfg file toggle for it. All it requires is for 0/0 magicka to be treated as 100% rather than 0%, so I really don't see how that's regarded as anything more than an odd and overlooked implication of magicka percentage being retained through changes in Int.