I couldn't see this in the FAQ, but excuse me if I missed it.

If I'm a new KF member with, say 24000 miles and take a 10000 mile flight then do the additional 9000 miles normally carry forward?

I'm asking because I had a this situation arise as a result of a manual claim/adjustment and the miles beyond the 25000 were discarded and balance reset to zero after that qualifying flight.

I'm guessing that's just they way they work - but it seems rather mean spirited of them.