This has happened to me a lot more since June time -I believe they moved held card details into SAP around then based on something a GGL agent told me.
I have corporate cards that now must bill as personal (works for me as it saves a fee), some cards duplicated as stored in my account where only one will work and other times I have to re input the card number. I’ve probably had to call GGL to make 3/4 bookings since June that just wouldn’t stick at all online. I’ve also had many temporary problems where I have to walk away and come back an hour later. Last week I had a “booking failed” page with a “contact us to discuss it” despite card being billed. An hour later booking confirmation came in.
That being said 70% of my bookings go through fine… and never seem to struggle to pay any change fees. I mean that’s 30% too low but… BA