IF you try, using multipleupload, to upload a couple of files and one of the is bigger than the value of upload_max_filesize it will fail without any warning

In nginx error log there is the following error present

2014/05/16 15:28:17 [error] 6459#0: *27 client intended to send too large body: 1464299 bytes, client: 192.168.2.204, server: ezp5, request: "POST /ezmultiupload/upload/63 HTTP/1.1", host: "ezp5"