Hi Justin, having this issue, I have a Sansung Smart TV with an ATV380
Hi Justin
I also have this issue although it is a bit irregular.
I am directly linked to the TV via HDMI. Samsung Series 5.
Settings on auto detect initially and then moved it manually to 1080P-60Hz (automatic also picked up 1080P-60Hz.
For a recreate attempt, try to set the TV to turn off while streaming video from XBMC (not the sleep function). Once it turns itself off, turn it back on. Most of the time the box remains on, but there is no signal detected by the TV (or at least it says the signal is not supported).
Hope this helps.