The MC-Client will ignore specific packages if there is not a minimum amount of time between them (i suspect a client-side game tick and two packet queues depending on destroy or create events. Rather than using only one queue to keep the packetsequence in order).

Unfortunately i dont know how to reproduce this problem without altering the server code. In theory it works by:

Case 1 (Problem occuring) :
1. Having an entity ( ID = 1)
2. Sending a destroy-packet ( ID = 1)
3. Sending a spawn-packet (ID = 1)
The spawn-packet will be ignored and the client wont track the entity with ID = 1 again.
(This might happen with network instability or high-pings and routing-changes)

Case 2 (No Problem occuring)
This does not happen if:
1. Having an entity ( ID = 1)
2. Sending a destroy-packet ( ID = 1)
3. Wait some milliseconds on the server-process
3. Sending a spawn-packet (ID = 1)

Code Example for # Case 1:
Packet destroy = new PacketPlayOutEntityDestroy(entityId);
player.sendPacket(destroy);
Packet packet = new PacketPlayOutSpawnEntityLiving(entityLiving);
player.sendPacket(packet);

Code Example for # Case 2:
Packet destroy = new PacketPlayOutEntityDestroy(entityId);
player.sendPacket(destroy);
Thread.sleep(50);
Packet packet = new PacketPlayOutSpawnEntityLiving(entityLiving);
player.sendPacket(packet);

Workaround
As this problem is dependent on the entity-ID it is possible to trick the client by changing the entity-ID
1. Having an entity ( ID = 1)
2. Sending a destroy-packet ( ID = 1)
3. Change the ID of the entity fom 1 to 2
4. Sending a spawn-packet (ID = 2)
This scenario will not present the bug.

This Bug can result in some common things like:

• Items that are impossible to pick up
• Invisible entities/players for some players
• Visible entities a player is not able to interact with

This might be considered a duplicate of MC-65040 but as this ticket describes a very specific way to create this condition it may be either another problem or a sub-problem because MC-65040 might be caused by different things.