I am running into a strange issue. After switching to Google Cloud, all my upload API endpoints are failing. The file is being uploaded successfully to my temporary directory, but it seems that the middleware is resolving before ctx.requests is populated with the information about the file. This might only occur on highly spec'ed servers.
From this koa issue and comment, it was recommended that instead of .then(next), you resolve(next()). I didn't have time to try this out myself so I just switched to another upload-handling middleware, but this may be something that might be helpful.