Summary:
Sniffer egg particles do not appear when placing an egg using a command on a moss block. If you replace a non-solid block (for example a torch) the particles will appear correctly (if you ignore the incorrect standard appearance of particles MCPE-169594). If you replace a solid block, particles appear over a large area, just like when using bone meal.

Steps to reproduce:

1. Place the moss block.
2. Place the sniffer egg on moss block using /setblock.
3. Break the egg.
   particles did not appear
4. Place a torch on the moss block.
5. Place the sniffer egg on moss block using /setblock.
6. Break the egg.
   particles appeared
7. Place a grass block on the moss block.
8. Place the sniffer egg on moss block using /setblock.
9. Break the egg.
   particles appeared over a large area

Observed results:
Particles appear incorrectly when placing a sniffer egg using the commands.

Expected results:
Particles appear correctly when placing a sniffer egg using the commands.