Just try to get evidence with this kind of other settings that BW On reject or stop wrong time captures.
Also please test overall can you find any effect using Trigger Noise Reject ON. I think previously you tried an no effect. But now you have more experiment with this fail so it is god to ask again.
Previously I tried trigger noise reject on and that did have an effect, but it didn't prevent the issue entirely, at least as I recall.
I'm running another test now with trigger noise reject enabled, and we'll see how that works out.
After that, I'll run the 20 MHz bandwidth limiter test (with trigger noise reject disabled). Last time I tried that, I wasn't able to reproduce the issue, but it's always possible that I didn't give it enough time. This time I'll give each test something like 12 hours or more.
That said, it looks like HendriXML has managed to reproduce the issue using an AWG signal, and that's really excellent, because it means we can give Siglent a fairly foolproof way to reproduce the issue themselves and, thus, track it down and fix it.
I really hope Siglent takes this seriously (the only reason I might believe they wouldn't is that there is a UI hang bug that I've had extensive discussions with Tautech about, and Siglent confirmed they were able to reproduce it. And yet, quite some time after that, they still haven't released a firmware upgrade with the fix to it).