Error validating callback ID

We have the same issue on one of ours app since the 12th of August (same day of OP).
- Yes, it is happening every time on the two Custom Workflow Action we have in an app
- No, callbacks are not older than 24 hours, they are minutes old
- It’s a url, the callback id is obviously a string
This is a recent correlation ID for the request:
84eff850-65a3-462c-b2ac-ce8f7826c0b8
Called URL (redacted information for privacy purposes):
/automation/v4/actions/callbacks/ap-xxxxxxxxx-xxxxxxxxxxxxx-1-0/complete
Response:
{“status”:“error”,“message”:“Error validating callbacks”,“correlationId”:“84eff850-65a3-462c-b2ac-ce8f7826c0b8”,“errors”:[{“subCategory”:“ExtensionCallbackValidationError.CALLBACK_NOT_FOUND”,…