It's nothing to do with IAG.

The FQTV field can hold multiple entries. This is a design feature, not a bug.

For example - say you're on an interline ticket on, say, BA and Lufthansa. It should be possible to associate more than one FFP number with the reservation - a *A one (to catch the Lufthansa miles) and a 1W one (to catch the BA miles). In such a situation, there is only one "valid" number for each flight so there is no doubt about where the miles for each sector will post.

The problem arises when you add two numbers from the same alliance - meaning that for each flight on the ticket, there no longer is just one "valid" option. In all likelihood (though it depends on the particular system that decides on where miles should post), the first valid number entered is the one that will be used. When this goes against the flyer's wishes - which nearly always will be the case, given that the reason they added a "new" number is cos they don't actually want the "old" number in there anymore - it leads to the outcome the OP has encountered. There are hundreds of posts about this very topic on these boards, concerning a broad range of partner airlines.

It's easy for airline staff to ADD a number, but their systems may not always actually allow them to REMOVE a pre-existing number (if a number has already been entered).

That's why it's better to act strategically, rather than throw yourself at the mercy of systems that were not built to allow this flexibility.

Or just consolidate all your flying in a single account per alliance, which is the default thinking behind the system design, and a strategy that works for the majority of the flying public

It's also possible to book BA tickets from BA without logging in to your BA account and without quoting/adding your BA number and therefore without ever associating your BA number with that particular ticket if the plan is that those flights should credit to IB...

Better yet, if you want complete flexibility, never book any BA or IB flights while logged in with either account, and never give a number during the booking phase - and then you can decide freely upon checkin which of the 2 programmes you want those flights to be credited to and which FFP number to quote. You could even delay that decision until after completing all travel (retrocreding).

If a pax has the FFP changed at check in and the paper boarding pass has the new FFP, and doesn't play lounge games flashing old FFP card, pax should have the flights credited to new FFP, irrespective of how or why the old FFP was in the booking.

The whole FQTV is interesting but irrelevant, whether OP made the BA bookings signed-in purposely or inadvertently doesn't matter. Unless BA has CoC/T&C saying the first FFP on the booking will forever be and can't be removed or changed, even if check in prints a BP with new FFP.

BA/IAG are playing hardball trying to make lives difficult for exBAEC folks trying to switch to another FFP, but them refusing to debit a miscredit flight is too far.

Well well...

i do need to use some benefit still. lol, why cant I?

Sigh