Hachima

1/5 - PDX-SLC - Upgrade to F at T-72 (-15 min)

I was somewhat surprised as this was the first automatic F upgrade I've seen recently. I've had to manually process my last 4 F upgrades in December (for the same PDX <-> SLC flights)
Path 1: I get the Upgrade to C+ email, I go online to choose my seat and I can choose an F seat for 'FREE'.
Path 2: After the C+ email it still asks me to pay to choose an F seat (maybe a website bug as explained below) So I untick my upgrade to First request, save, recheck it and save and it upgrades me to F and then I pick the actual F seat if I don't like the auto selected one based on my preferences.

At T-73 There were 15/20 F seats available. At T-72 (-5 min) there were still 15 F seats available but it showed I could change to F for 'FREE' but adding it to the cart asked me to pay so I canceled. At T-72 (-15 min) I get an email from AMEX GBT that I've been upgraded to 'Business Class' with a seat assignment at check in. So I go to delta.com and see it was now asking '$99' to change to a different F seat... I was stuck in my current seat (but an F seat with the OU fair class) on the web. However on the mobile app I was able to change my seat for free and it was accepted. This is what I see as a bug in the logic of the website vs mobile app.

Maybe this is a sign at a fix from having to manually make the upgrade change. This may not have changed but it seems like requesting both C+ AND F was resulting in getting assigned a C+ upgrade when you were qualified to get an F upgrade. However at the same time I suspect I was bypassing diamond and plat members (I'm gold) that were also given a C+ upgrade but were on the waiting list for F.