I haven't ben able to get to the bottom of this and the Ford bot did nothing more than say take it to the dealer which as you have found out is useless. Since it's specific conditions that cause it it's going to be difficult to isolate. Hopefully someone with this issue will be able to locate...
I thought I was one of the few to notice this. LOL I found it really annoying when it seems so sluggish when first taking off and then HOLD ON! Eco mode seems to balance it out better for me as well.
Did anyone find a definitive answer to this issue? My new 2023 Wildtrak is doing the same thing. When going over whoops offroad, seemingly when the front end unloads/rear end loads and starts coming down there is a heavy thud, not metallic, more like maybe a suspension bushing. You can hear it...