+1
Also would like trigger to work no matter if video or source is in program out, even if video is in preview or just playing out to assigned output, if there is a trigger listed it should activate or function.

To set the scene, The audience is sitting inside a old barn facing a projection screen which gives a view of the outside landscape and with artifacts located in different parts of the barn.
A SUV pulls up with a woman talking to someone on her cellphone as she walks up to
the barn entrance "screen one" then enters the barn and appears on "screen two". She ends the conversation, with her flashlight looking around the barn just as a storm suddenly rolls in with thunder, lightning and wind blowing.
just as a land surveyor from the past appears at the barn opening. There's a lot more to this video and flashlight movement with thunder, lightning and wind effects with other characters from the past in this video,
but I thought this was enough to give a reasonable demonstration.
I built a simple mockup to demonstrate the use of vMix to trigger a DMX spot light to simulate a flash light, Strobe light for lightning effect and a power relay to turn on a fan for wind effect.
This was done with scripts and using the new OnPlaybackTime trigger to call a script that calls on a command line that sends a midi command to my Chauvet DMX controller to activate preset scenes.
There are two videos being played back in sync that are started by a countdown clock which automatically resets and is triggered to start the countdown again at the end of the video.
Of course the countdown can be adjusted to any length or controlled by a stream deck for manual control. All three sources are output through SDI to monitors in place of projectors for this proof of concept.
The idea is to replace older very expensive automation equipment (AMX in this case) with a off the shelf solution for aprox. $5k
Video here= Demo video

I had the same issue, I tried setting the frame rate to match as suggested in other posts, but no improvement. And this is on a obsidian based system. So fortunately I had a BMD monitor card with HDMI & SDI out, so I connected that to my Multiview monitor and assigned output 3 to it. That worked perfectly.