I've done several steep descents here in Colorado and have never had an issue. However, I exclusively drive in Engage with 1-pedal OFF.I doubt it for his recent drive. The mountain drive Patrick just did (after the update) was on I-70 through Colorado. I've done the same drive twice (Denver-Vegas). There's regen coming down from the Eisenhower Tunnel at 11,000' and Vail Pass at 10,000', but that's never been a problem for the MME on interstates. Presumably because interstates are designed to maintain high speed without harsh switchbacks where you have to slow hard into the tight curves.
Even on 5-6% interstate grades, it only need gradual regen over many miles rather than hard bursts where you're repeatedly speeding up and slowing hard into the turns like the Mt Evens road, and the Norway road.
A real test would be driving back down the Mt Evans road again, or a similar road with hard, steep switchbacks.
This is what I reported a few weeks ago as well as another owner in New Hampshire. I suspected a softer bug...[Updated with response from Ford Norway]
Courtesy of Motor.no:
This was a pretty interesting article and reveals a similar issue to some of our friends in the West on steep mountain descents. Apparently in the last 14 days, six Mach-Es have bricked themselves from the heat generated during long downward slopes in this one little town. Ford has said that a patch will fix it, but it's currently only available at service centers and won't be OTAed until Sep/Oct.