This bug is pretty strange and the way I found it was pretty random! If you die while looking in a chest and in that same tick the chest gets set to air the death string will not appear below the "You Died!" string!
This may seem confusing that is why I made a video about it that will explain it!
https://www.youtube.com/watch?v=0Nr5pTlg11M&feature=youtu.be
The video is made with the optifine mod but I tried the bug in vanilla and it still happens in the same way!
This is a duplicate of: 121004 that got invalid because I used optifine!