Undead mobs of all types (zombies, zombie pigmen, skeletons etc) often times do not notice turtle eggs or try to pathfind towards them to destroy them. They can notice the eggs, but it usually takes about 30+ seconds. They should instantly notice the eggs as soon as they are within range of them.

*How to reproduce
1. Spawn a bunch of undead mobs
2. Place a turtle egg somewhere they can reach it

You should observe that the mobs don't do anything to the egg or notice it at all. Given time they might notice it and trample it, but they should try to destroy it immediately.

This bug has been in the game before MCPE-36244