What does unmatched transactions mean on Merchant Reports?

Why are unmatched transactions showing on my merchants redemptions reports for my program?

Unmatched transactions can be refunds or the following:

A purchase is always made in 2 steps.

  1. The money is reserved from the card
  2. The reservation is either completed or reversed. (usually the day after)

BUT, sometimes when a reservation is completed several days after, that completion gets a different ID in our system and that transaction is then seen under “unmatched transactions”.

So a normal transaction that is completed “fast” has the same transaction ID in our system.