What driver versions have you tested with? Are you seeing this problem just after a driver update, therefore you pointed this as a bug in the latest drivers?
Have you tested another model of TV in the same port? Or tested the TV in another system through DP?
Please post the dxdiag from the system being affected to have more detailed information on the system that you are using.
126.96.36.19907, 3111, 3186, 3282
I think it worked ok with and old vers. from april. I don't remember the number and now I can't find that vers. I update it after a couple of days and a then I discover the problem black screen only - no power saving mod (stand-by)
Asus Z87 Pro (last BIOS vers 1405), Intel 4670K connected with a Display Port Cable v.1.2 with monitor Dell U2713HM.
W8 Pro 64bit.
I don't have another TV(monitor) with DP port.
As I wrote Dell U2713HM stand-by works perfect with a VGA card (Nvidia) with DP cable.