After getting the update today. I went to see to my pigs in their pen heard strange noise and it had spawned a load of Zombie Pigmen in with my pigs. This is in the overworld on the realm.

Pic attached, it won't let me attach anything, tried in different formats .png and .jpg just says:
JIRA could not attach the file as there was a missing token. Please try attaching the file again.

can email the screenshot if you want it