This feels like one of those “enjoy it quietly and don’t touch anything” situations.
Iberia’s reissue logic can get weird when you mix cabins and then change a segment. Sometimes the system just reprices the remaining legs into the higher cabin to keep the fare consistent, especially if economy availability is tight or the original fare bucket no longer exists.
The scary part is the $10k fare showing on the email. That’s usually the “current value” of the ticket, not what you actually paid, but it definitely makes you nervous about a clawback.
If it’s ticketed, seat assignments are confirmed, and you’re not seeing an extra charge on your card, I’d probably stop poking the bear. Calling in can sometimes cause an agent to “fix” it in the wrong direction.
I’ve seen a few reports like this where people flew just fine and never got charged more, but there’s always a non zero risk Iberia catches it later. Screenshot everything and maybe don’t make any more changes unless absolutely necessary.
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