We've had a few gravy donations flagged by donor relations, which were captured and settled at the backend processor, but that did not make it into CiviCRM. There have been a few explanations: Chinese characters breaking API calls and initial fraud scores rejecting transactions that Adyen later authorised.
However, some transactions remain unresolved and have required manual re-importing. When we trace the logs for these cases, we see that a transaction starts with a capture_pending status. The pending transaction resolver picks it up and later drops it because its status has already moved to capture_succeeded, suggesting it doesn't need resolving. The problem is that our system never recorded that successful capture, even though we received the capture_succeeded webhook from Gravy. This suggests the capture job itself is either not being created or is failing to process correctly.
A recent example is https://wikimedia.gr4vy.app/merchants/default/transactions/8b79cf90-1a4d-4872-872c-ba1ac3ef9e39/overview. If you follow the history of this transaction before Sept 4th, you will see it gets lost. I had to manually import it into CiviCRM on September 4th because I couldn't understand why it hadn't been imported initially. Therefore, log data from after that date won't be helpful.
Happy hunting!