I also have the issue reported by two previous posters, however in my case it affects everyone in the raidframe. This is a new bug, because I have previously used both Grid and Mana Bars, and the text used to be on top. After recently updating my Grid to newest version, the manabar seems to be on top.
And this is now after the update:
As you see I am also using Center Text 2 to display health deficit, so it is kinda annoying.