Put the summary of the bug you're having here
What I expected to happen was...:
I thought the Ender Dragon Egg appearing next to an observer block would trigger it.
What actually happened was...:
When the Ender Dragon Egg appeared next to the observer block, it did not trigger it.
Steps to Reproduce:
1. Either place a bunch of observer blocks with pistons next to them and keep clicking on dragon eggs until one lands next to an observer block, or...
2. Fill up the radius of a dragon egg's teleportation with blocks and leave one block free so that the egg must teleport there. Make that free block next to an observer block.
Now it's included in MC-107664