@blk150tx - as software performance tester/analyst, I must say you've done an excellent job isolating & documenting the sequence required to reproduce this issue. In-house customer recreates of software performance problems are very difficult for me, but I think you've nailed the operating parameters and sequence to reproduce the problem.
From the sounds of it, you work at a large building complex with a designated speed limit before you get off the property (I had something very similar pre-COVID) where the transmission is confused because you haven't gone above 20 MPH or out of 3rd gear for more than a 1/2 mile, then when you need to drive "normally" the transmission "loses it brains" shifting out of 3rd?
Since these transmissions are self-learning (i.e. TCM adapts to your driving style programatically), I'm wondering if that first 1/2 mile under 20 MPH drops it into some sort of "farm" mode where it doesn't expect to go above 20 MPH, and then reacts violently when you get onto public roads with normal speed limits.
I think you're onto something here and it is unfortunate your dealer is not willing to react/respond, as I think you could reproduce on-command if they were willing to have a diesel or transmission tech meet you at work. I'd post the video recreate on YouTube and maybe someone from Ford Corporate will react if you get enough views.