I believe this is similar to an issue that arose when people transferred SPG to Marriott, but this really hurts...
I had 170,051 Iberia Avios expire on me less than 18 months after I moved 170,000 points into the account.
51 miles of those points were in the account for 36 months and were set to expire. The other 170,000 points transferred into the account became subject to the same expiration date even though they were not in the account for 36 months (this is because transfers in --- whether from Amex or BA do not count as activity).
The 170k was transferred into the account for an immediate redemption, which I had to later canceled (and paid a few hundred dollars to have the Avios redeposited) less than two months before they expired. I really did not know they would be subject to the expiration date of the 51 Avios.
I called several times and was told I'm SOL but advised to send an email. I have yet to receive a response.
I know Iberia is not known for their customer service (and this may be within their rules) but this is painful.