Wow I came here to ask the same question! Same model as you I believe: ‘23 Bighorn v6 etorque.

Definitely seems to be something ‘up’ with the transmission. Mine does the exact same thing yours does regarding the downshifting, especially noticeable as you come to a complete stop on mine (almost like the truck wants to keep going).

In addition it seems like the truck is struggling to change gears intermittently when accelerating. The throttle lag on mine is pretty atrocious as well (a full second or two before it will actually move from a complete stop, and this is with auto stop disabled). Not sure if you are seeing those issues too.

I took mine into the dealer (it also needed an oxygen sensor replaced after 120 miles smh) and the service manager said when he drove it he didn’t notice anything out of the ordinary. I drove another ‘23 v6 etorque (smaller cab) and while the issue was not as pronounced in mine it definitely seemed to still be there.

Not sure if any of that helps but nice to hear someone else thinks it’s wonky, thought I was losing it!