On 2 separate occasions while towing a 6,500 travel trailer on flat roads, with my 2020 XLT w/hvy dty tow pkg and only 17K miles, there has been a failure in the tow/haul operation. All drive modes suddenly and without warning while vehicle is moving, become unavailable - the features like hill assist, sway/skid control, speed control, etc. are announced individually on dash display as inactive. The vehicle is still operational, but only in normal mode - and without the features mentioned earlier. Dealer was unable to find any stored failure, fault, or error codes in the diagnostics on the first occasion (about 3 months ago) - told me to bring it in when it occurs. Today, when the second failure occurred, I was 20 miles from home, towing same trailer. I have made another appointment but am very interested if anyone else has experienced what I've described towing - or not - when the drive modes suddenly fail and the default - normal - is the only option.