The merge process failed because it detected a mismatch between the replication metadata of the two replicas, such that some ...

The merge process failed because it detected a mismatch between the replication metadata of the two replicas, such that some changes could be lost leading to non-convergence. This could be due to the subscriber not having synchronized within the retention period, or because of one of the replicas being restored to a backup older than retention period, or because of the publisher performing more aggressive cleanup on articles of type download-only and articles with partition_options = 3.