Only one example of that found:
Nov 15 07:52:05 ms-fe1001 proxy-server: HTTP status code mismatch. Mediawiki: 200 Thumbor: 503 URL: http://upload.wikimedia.org/wikipedia/commons/thumb/1/16/Gran_canaria_llanos_de_la_pez_roque_nublo_teide.jpg/801px-Gran_canaria_llanos_de_la_pez_roque_nublo_teide.jpg
| Status | Subtype | Assigned | Task | ||
|---|---|---|---|---|---|
| Resolved | • Gilles | T121388 Service-based thumbnailing re-architecture in production with Thumbor | |||
| Resolved | • Gilles | T139606 add thumbor to production infrastructure | |||
| Resolved | • Gilles | T150641 Investigate differences in status codes between thumbor and image scalers | |||
| Declined | • Gilles | T150761 Thumbor 503s on an image Mediawiki renders successfully |
Another instance:
Nov 14 12:51:52 ms-fe1001 proxy-server: HTTP status code mismatch. Mediawiki: 200 Thumbor: 503 URL: http://upload.wikimedia.org/wikipedia/commons/thumb/3/39/%D0%9D%D0%B0%D0%B1%D0%B5%D1%80%D0%B5%D0%B6%D0%BD%D0%B0%D1%8F_%D0%9A%D0%BE%D1%80%D0%BE%D0%BB%D0%B5%D0%B2%D1%81%D0%BA%D0%BE%D0%B3%D0%BE_%D0%B4%D0%B2%D0%BE%D1%80%D1%86%D0%B0._-_panoramio.jpg/1536px-%D0%9D%D0%B0%D0%B1%D0%B5%D1%80%D0%B5%D0%B6%D0%BD%D0%B0%D1%8F_%D0%9A%D0%BE%D1%80%D0%BE%D0%BB%D0%B5%D0%B2%D1%81%D0%BA%D0%BE%D0%B3%D0%BE_%D0%B4%D0%B2%D0%BE%D1%80%D1%86%D0%B0._-_panoramio.jpg
This one seems to be completely intermittent and very rare. Re-requesting those thumbnails works just fine.