Nuendo Live crashing on multitrack playback

I have been using Nuendo Live for years for live multitrack recording. It generally works very well and has been reliable. We just took delivery of a Yamaha DM7 and I plan to use it for live recording.
I have a PC running windows 11 that I have used for a couple years for this purpose on a CL5 and QL5, both with satisfactory results.

The problem I am running into is this: The PC records flawlessly, 48 tracks for over an hour at a time (a full band set at a multi-band show…). What it does NOT do is playback those tracks for the purpose of a virtual sound check (or for any other purpose). The tracks will play for around two minutes, then the performance meter wil spike and the playback will stutter for about a minute, then it will usually resolve.
Facts:

  • 48k, 24 bit recordings
  • DVS is the driver that streams the tracks to the Yamaha consoles
  • If I do not have the PC mounted on the console (meaning, there is no streaming happening), the tracks will playback without a hiccup, though they cannot be heard because they are not going anywhere
  • Recording works perfectly, performance meters are barely visible, and there is nothing on the “disk” meter at all (Sandisk SSD, USB3)
  • Playback and recording both work fine in “Reaper”, so it does not seem to be a computer or DVS problem.

Things I have tried:

  • Toggling the Processor Scheduling from “Programs” to “Background services”
  • Clean reboot
  • reinstall Nuendo Live, DVS, Yamaha console extension
  • Swapping to different USB ports (both SSD AND NIC)
  • Using a Realtek RTL8156BG Chip NIC dongle
  • Swapping from the DM7 to a QL5, same behavior exists on both
  • All sorts of tweaks and optimizations for PC.

DPC Latency checker indicates Interrupt to process times of less than 100, ISR under 100, and DPC under 150.

I believe this is a Nuendo Live issue, mostly because Reaper works fine with the exact same settings and files. Has anyone seen this? Any solutions I have not thought about? I have spent two entire days on this and I’m stumped.