Timing of Looping Show Drifting Over Hours of Running

[mrw]

Hi,
I have ESA2 running with a SLESA U9. I used OBS Studio to record my screen to gather data on when each scene really activates. I am running a show that consists of one channel for 30min and then another channel for 30min. I have the scene set to loop continuously. Even though I have only two steps, and they are set to 30min, they actually seem to run for 1 hour 10 minutes instead of 1 hour as expected. Here are the times the second step of the program started:
Video time/Time date from windows desktop clock.
1:36:37 10:24 5:17pm
2:46:23 10/24 6:27pm
3:56:24 10/24 7:37pm
5:06:11 10/24 8:47pm
All are 1hour 10 minutes apart.

I am running the program from the editor. I click the play button and let it go, with it connected via USB.
Does the sequence running not use the local PC clock?

ESA2_30min_step_program.jpg (19.69 KiB) Viewed 22568 times

ESA_step1.jpg (55.72 KiB) Viewed 22568 times

ESA2_step2.jpg (46.46 KiB) Viewed 22568 times

Any help in figuring out how to keep it in step with the local PC clock would be greatly appreciated.

MW

[mrw]

Are there additional details I can provide that would help diagnose the problem? Is there something with the architecture of the system that would allow for/cause timing drift?