As other pointed out, this is probably just down to terrible airline IT. I don't know if AF/KLM are worse than others but it's remarkable just how bad it is.
Recently they had a bug where once you selected a seat for one flight in a booking you were blocked from any later seat selection in that booking. The only way to fix it was to call customer service.
I'm lucky enough to have access to the platinum line. You get to talk to people who are pleasant, competent and have sufficient authority to actually get things done. This should be the experience for every call to customer service but I guess it would be too expensive.
Recently they had a bug where once you selected a seat for one flight in a booking you were blocked from any later seat selection in that booking. The only way to fix it was to call customer service.
I'm lucky enough to have access to the platinum line. You get to talk to people who are pleasant, competent and have sufficient authority to actually get things done. This should be the experience for every call to customer service but I guess it would be too expensive.