when you summon a wither skull it is invisible
1:type this in a command block:/summon WitherSkull ~ ~2 ~-1 {ExplosionPower:10,direction: [4.0,0.5,1.-5] 2:}
2:build a wall of blocks in direction EAST
3:then you will se that the wither skull is there,but not visible
you can also download my save WITHER SKULL BUG
Duplicate of MC-31412 - If you have not, please use the search function in the future, to see if your bug has already been submitted. If you could not find the original report, please comment with the keywords you searched for.