Red Sand Turns To Sand

Unable to recreate, but just killed an Enderman who was holding a Red Sand block and when he died he dropped a normal Sand block! If I see another I'll take some pictures before and after killing him!

Managed to find a couple of examples of this in action, here is a short video of me killing two Endemen that were holding Red Sand blocks and showing that they drop nomal Sand blocks when killed.
Endemen Red and Sand