Please, please, please.
MAKE THIS INFORMATION IN A BIG WINDOWS TO LET PLAYER KNOW.
Sorry for caps, but...

I can't count how many players i've just raised who rush like madman into the boss again without waiting a single heal (even instant one) and die again due to wide raid aoe.
This mechanic exists in the game, and the only way to know it is to spread the word while it's totally tied to the battle system with everything else.

or...

Just put the invuln icon on someone who just raised... and make it fade off upon using an action.
It's pretty simple.
You made more visual icon through time (battle gauge, shields, 0,1=>0,9 life percentage...)
It could be easy to implement.