i originally posted this as a drop rate bug but it has been confirmed that this is functioning properly so i am assuming the issue i am experiencing is wither skulls impacting the ground after the wither has dropped the star and destroying it. this item should be protected from time lag explosions caused by wither projectiles that were still in flight at the time the item was dropped.

SEE MC-3992

i have confirmed the occasional disappearance of nether stars on a flat bedrock map with no area hazards other than the wither it;self