Hi =) I had some similar issue in Unity. The solution was to make the player a child of the platform object while you are standing on it (if this is a single player game).
Yeah , I know but because I was using a Character Controller instead of a RigidBody I couldn't the correct results.
But wouldn't parenting the player mess with the player's position and rotation.. I did this once but my movement axis got messed up.. :(
Oh, I guess it depends on how the movement is implemented: based on global axis vs local axis..
Damn, Gotta look into it once.. been breaking my head for such a simple thing then.. Thanks for letting me know
I hope it'll work =)