Crash When Loading World (New Chunks)

While flying around loading new chunks to see how the new snapshot's chunk loading improvements handled, i crashed and the launcher gave a crash report, however it refused to auto-submit it as it thought it was modded.

You can see the crash report here: http://pastebin.com/LajS3U1f

Also i will attach a screenshot of the launcher claiming it to be modded.

Thank you for your time,

HexxiumGamingYT