I can confirm this new method worked for me! I took my 2017 GMC Yukon to the dealer with the same issue. Said they compared it to the 2019 model and that does the same thing, and that there was nothing they could do for me.
I almost gave up trying to get the but behind the pedal mount. After losing 3 nuts somewhere under the insulation (lol) I finally got it on. And I can confirm this is a easy fix so far.
before I had shoved 2 Allen wrenches behind the pedal mount and used electric tape to hold them there, which worked good too. This way is a lot better lol!
Thank You!