When you open your inventory the player head will shake... From the viewers perspective.. Keep in mind I could only see this with a texture pack and the texture pack has the inventory clear... See video for more detail.. You should be able to reproduce this with a lower fov.. If not here is a link to the texture pack:
http://mcpedl.com/dynamicduo-pvp/

EDIT: It happens without the texture pack... But if Screen Resolution goes into play... Then I keeping the link.

I doubt this could be a texture pack issue. Also I looked up the issue to confirm 0 duplicates.... But I saw the same issue(Fixed) for Minecraft PC(java)

https://youtu.be/vDyf2qT8ADI

Is this a duplicate? I don't think so.. If it is sorry ;(

Also sorry for including a YouTube link... The video is over 10MB... Which isn't hard to do(please make it 50MB <3)

Steps To Reproduce

1.Lower FOV to 30.
2.Open inventory.
3.Take a look at your master piece.
EDIT: I know fov at 30 is rare to have it at... So why bother? But what about my texture pack? Clear inventory