I think that might be the cause of my pop up jail issue - my spending on my Green card has tailed off the last few months in favour of my Citi Premier. Looks like a preference for simplicity in account management by paying less bills comes at the cost of pop up jail. Will try to step up my charges on the Green to see if that fixes it. Thanks @sudoer !Kinda gobsmacked, but I put a few thousand worth of spend on the card later that evening, transaction has posted and I'm now OUT of pop-up jail and successfully approved for my 3rd GT!