Non-player entities cannot travel through unlinked nether portals

The bug

Non player entities cannot travel through portals if it's not generated on both sides.

How to reproduce (from Jeuv)

1. Create a new world and create an unlit portal frame.
   • If in an existing world, create an unlit portal somewhere far from any existing portals in both the nether and the overworld.
2. Put a boat in the portal frame
3. Check the boat's PortalCooldown tag by typing

/data get entity @e[type=minecraft:boat,limit=1] PortalCooldown

, note the tag is at 0

1. Light the portal
   → Observe that the boat is not teleported but PortalCooldown is now at 300.

Original Description

Basically my bug is that sometimes pig-men come through the nether portal, to the overworld. Issue is that I cannot seem to push them back into the nether, by physically pushing them into the portal whilst it's lit. Not sure if it's changed that the pig-men need to stay there longer (in the portal) to transport. I had one there for around 8 seconds, but didn't get transported.

Note: I haven't gone to the nether, so idk if it's registered a new world for the nether, or if I'll have to go there myself to generate it to then go back and push him back in. I'll check that and update on if that resolved the issue, and then if this even is a bug.

Update: After going to the nether, and back to try pushing him back in again, the issue is still the same. The pig-man won't be transported back through the portal.

Restarting game didn't resolve it either. As can be seen on the video attatchment.

Issue still remains in the newest version of Minecraft (1.14.1)

However I've found out if the pigman goes into the portal on his own, he will be teleported, but if I try pushing him in he will not teleport.