Originally Posted by
s0ssos
Oh, I guess the answer was the devaluation of the GBP (and Avios being linked)
??
The value of avios is not linked to the value of the pound (or any other currency)
The reason was as posited earlier and confrmed by the OP that they are part of a household account so the avios were taken pro rata from each acount and then returned from whence they came when the tiket was refunded.