I’m running 507 firmware and noticed that if I put the R1 into Back to back mode by pressing F1 whilst still cooling the current roast, pressing F2 doesn’t cycle the display to Cx for the fan speed. The +/- buttons do change the fan speed but you can’t see what it is. The display seems to be stuck on the last main Fan speed…
Is it just me ?
Me, too, identical…on 475 firmware.
Thanks for the info. I will look into it.
Followed up a more concise repro case - seems that if you have used F2 to switch to the cooling fan display before selecting BAC, then the display does show the Cooling number as expected. If the display is showing F0 instead when you hit F1 for BAC then when pressing F2, the display flickers briefly but always shows F0.
May be related and not sure if by design, but in BAC mode, if you get the cooling fan to C0, the roaster switches out to OFF mode without going through standby cooling which I can’t think is good. When this happens I quickly cycle back from OFF to PH so I assume the relevant fans are cooling the right things that are still hot 
I’ve seen this same action Stuart. So I’ve avoided using BAC since recovery time is relatively short compared to previous HotTop. I thought I had posted about it somewhere on Roast.World but I can’t find it so I must have dropped the ball. The worst part (at least in earlier f/w 475) was the bean-cooling fan shut off when cycling to PH which meant I had to winnow the beans and hope for the best.
Bruce