While I haven't seen this with C+, I've had a couple instances now where the upgrade to First request gets unselected for an itin somehow even though it's selected in my Profile. I had it happen for a return flight for my last booking and didn't notice it until I had checked-in for flight (and noticed I wasn't on upgrade list). I had to request that I be unchecked in to change the setting. Now seeing the same thing for a new booking as below.