Originally Posted by mre5765

The e-upgrade summary page has an option to show detailed upgrade activity for a given date range. I'd do that and see what was deducted and when.

Possible explanation.

Let's say you had two segments in a trip.

Segment 1 needs two e500s and segment 2 needs one e500. You check in, and segment 1's upgrade clears, but segment 2's does not (or you didn't request an upgrade at check in or before).

So 2 e500s from the 3/2009 pool get deducted first taking you down to zero. There is an irrop on segment 1, and you don't get upgraded on the replacement flight. Segment 1's e500s will eventually be credited back, but likely not that day.

Later that day, you upgrade segment 2, and it requires one e500. It comes from the 6/2009 pool because you are at zero in the 3/2009 pool because M+ upgrade accounting hasn't caught up. So 4 goes down to 3 in the 6/2009 pool.

If something like this happened, you can make the case to M+ that you should get an e500 back; the irrop isn't your fault.