Ran into this issue today.
On the takeaway, my arms were drifting too low and wide to my trail side, thus my arms were "fighting" against my lead shoulder rotation that should move down. Thus, the lower and wider my takeaway, the more my arms pull my lead shoulder to the right vs. rotating down. This move puts weight on my trail side because my arms have weight, and also because my lead shoulder was drifting to the trail side, thus I was getting into an out-of-balance condition on my trail side. This can be a very sneaky flaw that can go undetected. But when I start hitting thinner shots and weak fades, I now know the reason. Fixed it today mid-round.
Hope this helps others.
Good post, @GolfLivesMatter. Ingraining a proper backswing path is certainly key to a consistently solid swing. That's why I put down two sticks in this week's YT video, with the one for the club path angled slightly to the inside of the target line stick. We don't want to force it straight back, nor do we want to rip it to the inside. We've preestablished our inclined swing circle at setup; now we've just got to trace the circumference without modifying the axis.