500 returned from Modify an App Screenshot endpoint

I know 500 means an issue on the server. But the system status page is all green and I think the App Store Connect API has a history of incorrectly returning 500 instead of 4xx statuses, e.g. here. So I'm sharing this in the hope of getting some more information.

I am following the steps here: https://developer.apple.com/documentation/appstoreconnectapi/uploading-assets-to-app-store-connect

My PNG data is successfully uploaded to the URL contained in the Upload Operation for the screenshot. The next step is to confirm the upload with its MD5 checksum, which fails.

[15:59:27.289] DEBUG (74920): AppleUploadService: PUT https://northamerica-1.object-storage.apple.com/itmspod11-assets-massilia-200001/PurpleSource211/v4/d8/8d/4b/d88d4b7c-ef96-e3a0-bfab-b793903bf2db/taiz5B2iCIVeTQQlGZFfx4f2jMPAbVruq7JKHmykh7M_U003d-1768937158953?...
[15:59:28.727] DEBUG (74920): AppleUploadService: 200 OK
[15:59:33.735] DEBUG (74920): AppStoreConnectApiClient: PATCH https://api.appstoreconnect.apple.com/v1/appScreenshots/08e7802f-5a52-49a8-91c5-f4040721607a

{
  "data": {
    "type": "appScreenshots",
    "id": "08e7802f-5a52-49a8-91c5-f4040721607a",
    "attributes": {
      "uploaded": true,
      "sourceFileChecksum": "714d426fc4fb39f732dca9f481c7039b"
    }
  }
}
[15:59:34.359] DEBUG (74920): AppStoreConnectApiClient: 500 Internal Server Error

I can't see anything wrong with my request body.

Has anyone else encountered something similar or is this truly an outage?