Now, I had the same thing happen to me before.

Basically what I think it may be, during the day you are performing RC's but without really much effort or without actually debating whether you are dreaming or not, you just do it as it is a habit. You expect your hands to be perfectly fine and as we all know dreams are greatly influenced by expectation.

I suggest maybe taking a bit more time in performing your RC's and at least believing in the possibility of it being a dream, ask yourself where was I 10 minutes ago? how did I get here? etc.