Relates to:
When multiple Shulkers are at the same spot (this can happen in Survival) and they start shooting, they hit each other. Unlike described in MC-83838 (fixed), the ShulkerBullets now stay where they spawned without moving at all (however their NBT data is not corrupted).
This is very likely caused by the fact that only ShulkerBullets with Motion entries that are not 0 can damage an entity, but as the ShulkerBullets are already at their destination, they do not have to move.
Linked issues
is duplicated by 3
relates to 3
Comments 7
Relates to MC-83249
Looks rather like MC-83249 is a duplicate of this report or the other way around, at least the way to reproduce you described is the same situation this report describes.
Is this still a concern in the current Minecraft Snapshot 15w44b or later? If so, please update the affected versions in order to best aid Mojang ensuring bugs are still valid in the latest releases/pre-releases.