With multiple segments - your miles are gone if only one segment gets upgraded. Say you travel BOS-EWR-LAX. If BOS-EWR opens, but EWR-LAX does not - your miles are gone. You may want to watch that in the future and check for F first.

Only on international BF upgrade waitlists do you get your miles back if the BF segment does not clear. In this case you get the bonus of a free domestic upgrade - for your feeding segment.