There are a few reasons a duplicate OTA reservation can appear in Cloudbeds PMS, find below some of the most common causes.
1. A manually added reservation was set with an incorrect Reservation Source.
When a new OTA reservation is imported from myallocator, Cloudbeds PMS checks existing reservations from that OTA to make sure the incoming reservation is not a duplicate. It does that by checking all reservation IDs currently present for that OTA source.
If a manually added reservation was set with an incorrect source (for instance, as "OLD PMS" instead of "Agoda"), then Cloudbeds PMS will not be able to recognize that they are the same reservation. The update from the OTA will be seen as a separate new reservation. This results in the creation of one more reservation, what seems to be a duplicate.
To prevent this issue or correct it after it has occurred, make sure all manually-added OTA reservations have the correct source assigned to them.
2. The Reservation was manually added multiple times
If a reservation is manually added multiple times with either an incorrect source or no reservation ID, then there will be duplicate or multiple versions of that reservation present. This often occurs when a user does not check whether a reservation is already present or incorrectly formats a batch CSV reservation import.