A few notes on what was learned and what changes were made; royhen99 please correct me if I get anything wrong.
We discovered that, at least on my board, the STM32 wasn't seeing a change in state on pin pb6, which should have changed when the station signaled via CHAdeMO pin 10 that it was ready for current. Because of this, the car never requested current. Removing that check from the code and just requesting current right away, as the Zombieverter version of the code does, got me charging on some stations, but I was having issues on EVGo's Delta chargers. One wouldn't charge, the other would only charge after several attempts.
Based on the logs, the EVGo Delta stations were unhappy about the early current request. royhen99 then added a delay function to the current request (user adjustable), and this addressed the issue. At least for me, a setting of 100 (equal to 1 second) has allowed me to charge at EVGo's Delta stations flawlessly.
I am still planning further tests. I have only tested at about 5 chargers to this point. Next weekend I'm hoping to hit several more.
I can say definitively that this version of the FW, on Damiens STM32 + ISA board V3, with pb6 detection off and a 1 second current request delay
will charge at Delta chargers.
Here's a photo of my car charging at one while I went and got lunch.