Two changes to what happens when a generation fails.
Credits are always returned. A generation that timed out used to be charged with no refund — a status that took your credits and gave nothing back. It is gone. Every failed generation, whatever the cause, refunds what it charged, in the same ledger you can see on your account.
The reason is kept. Some providers reject a request in the first second — a reference image that does not pass their checks is the common case — and on one path that rejection was recorded as "failed" and nothing else. The provider's own message is now stored with the generation, so support can tell you what the provider said rather than guessing, and the next step is to show it to you directly in the studio.
Thumbnails are also written for every completed generation now, on every path, so the Library no longer loads a full video to draw a preview.