No worries, that was constructive discussions
As it was around 25 to 30 years ago when I was working on these wagons regularly, the mind dims a bit, but something you have just mentioned has made me think. The bellows spring on the seal may well have settled, because I recall having to change these seals, but not because there was visible damage. You could ask the person who has stock of these seals, to measure them, on the pretext that you want to check they are the correct ones, and if there is significant difference between yours and the new ones, then there is the answer, the spring has settled.