A few things have changed since my last update. The issue where the motor would cut out intermittently got worse. I contacted Rurui support and after many emails, photos, and videos, and tests, they sent me a new display and controller.
After I replaced these 2 items, and fixed some damaged motor wires, the bike performs far better. The controller appears to be a later version. I immediately noticed a big power gain especially in PAS 1. It used to top out at about 11mph in PAS 1 and not it is more like 13.5mph. The biggest difference is the power everywhere, and that it sustains that power even on long hills. I have now taken it on about 5 rides, including long hills in loamy terrain, steep hills, and some paved trails with long climbs. It performs so much better now. It no longer surges or cuts out like it had done since I bought it.
Upgrades since my last post
I replaced the 52 tooth chainring with a 44 tooth. This give me better low speed performance for off-road. It translates to about 18% more torque (and lower speed) from my pedaling. Of course this is a trade-off with top speed which is also reduced 18% but I ride mostly off-road and don't need the higher speeds. Now with the improved motor performance, and this addition climbing torque, I can climb hills I never could before.