I’ve encountered a similar issue with DADman 5.7.2.1 on the Avid S6. The Sum vs. Switch function seems inconsistent—especially when routing complex monitor paths. It looks like the behavior changed subtly from earlier versions, possibly due to recent firmware or software updates.
One workaround that helped in my setup was rolling back to DADman 5.6.5 to confirm whether the problem was version-specific—it was. Also worth checking your EuControl version and ensuring it’s fully synced with the latest DADman configuration.
That said, I recommend reporting this directly to NTP/DAD support with detailed logs—they’ve been responsive in the past.
By the way, if you’re integrating any control systems or companion tools via a mobile interface, I’d suggest checking out a Mobile App Development Company in Bahrain. Some of them specialize in broadcast tech and might help build custom solutions for these workflow gaps.
Let us know if you find a more permanent fix!