Xray/Chunks dissapearing still in 14w30b snapshot

I found a video about a possible xray exploit/bug in the ported MCPE graphical optimizations. It's not mine, but fortunately it's pretty self-explanatory:

https://www.youtube.com/watch?v=V3t8lzmTABQ

Could also point to a bug where some unseen terrain or caves are still being rendered although they shouldn't, but I don't know how intentional that is...