Guardians are not appearing in nether

What I expected to happen was...:
The guardians should appear in the nether when they get pushed through the portal.

What actually happened was...:
When pushed through nether portal on realms the guardians are disappearing. The entity count is not going up. It is very low as if nothing has spawned in the nether.

Steps to Reproduce:

1. Go on realms push a guardian through a nether portal.
2. Go to the nether.
3. They will not be there.