Blizzard Community Manager Tyren for MMORPG World of Warcraft has posted an update over at the game's official forum site regarding the character copy feature for the Public Test Realms or PTR.

According to the blue-poster, Blizzard has deemed it necessary to disable the feature for the mean time due to several reasons. Tyren explained further:

Character copies to the Public Test Realms are currently disabled while we investigate an issue that was found with the PTR character copies.

We currently do not have an ETA on when they will be reactivated, but will provide updates as they become available. Thank you for your patience.