when i want to create a supout.rif it takes a long time to create and the cpu was 100% after that a 19MB supout.rif created.then two autosupout created
i tried to send supout and two autosupouts to support but i think their mail server have problem because the auto reply mail does not came back
I’ve noticed strangeness with supouts now too.
http://forum.mikrotik.com/t/v-3-14-supout/23758/1
But mine is about 20MB 
autosupout.rif is made in case of a crash. probably something went into a loop and just filled your file with the same data, over and over …
it happend when i wanted to create supout . the supout.rif is 19.2 MB itself . i have sent an username password to support for access the router .