Hi Eddie
EuControl logs from my machine are here:
https://www.dropbox.com/t/e9toa6QvC8qICyvZ
Problem was experienced at 11:31 until about 11:34 on 26th Aug 2021 (in fact, this was when I took my video that I shared in my original post, so hopefully you can correlate the video with the logs).
Also FYI, Avid support have come back to me and said: "Please try clean uninstalling and reinstalling the EuCon driver. Also, try creating a new user account on your computer to check if the issue still persists." My case number is 04231216. I haven't tried either of these suggestions yet, pending your response to the logs.
Thanks so much for your help.