Thanks Ray - really looking forward to your interpretation of the logs.
Let me know if you need any additional data - I still have the ascom logs from my previous nights testing / older PHD2 logs. I didn't include them in the zip as they are not relevant to the PHD log I gave you.
And at the risk of beating a dead horse :), I think the problem breaks down into two parts:
1 : What triggers the DEC excursion in the first place.
Based on all the great info from Roland & Co, this can likely be eliminated by using more reasonable MinMove settings.
2 : Why the excursion spikes and then takes so long to be corrected (usually 15-30 seconds)
My interpretation of the graph (several corrective pulses over multiple seconds with no response, followed by a sudden swing and over correction) is that it looks like stiction. As the full swing happens over such a long time period (30+ seconds), I don't think it can be described as a "fast" oscillation. But I could be wrong - maybe I just need to re-calibrate my definition of fast :).
My concern is that I may be able to avoid this issue with less aggressive MinMove settings using my current short-focal length / large imaging scale set-up (which is pretty forgiving). But when I switch to a more demanding / longer focal length set-up the issue may return.
So, I'd really like to understand both parts of the problem - the initial trigger and the mounts (lack of) response to corrective pulses.