I am using two external monitors through my 5k iMac. The two monitors I'm using are a Sony Google TV and a Samsung 4k External Display. For the Sony TV I'm using a Thunderbolt to HDMI single cable. For my Samsung I'm using a Thunderbolt to Display Port single cable. Both monitors work perfectly when used individually, but when I plug in my Sony TV the TV has a delay in playback. Normally I adjust the offset to 100 milliseconds in Premiere and it works fine, but when both monitors are plugged in this option no longer works.
I have tried using a smaller 1080 monitor as my second display along with the 4k monitor and the problem persists.
Anyone have any ideas how to get the Sony TV to respond appropriately?