"Portal" block breaks when used with /fill command

Hello. This has been around for a while now, and it’s a shame as it’s a really cool feature that used to allow players to create custom nether portals, without the need for the portal frame itself.

How to replicate:

1. use the /fill command to place down a wall of portal blocks.

2. observe how the portal blocks will instantly break, with a glass smashing sound.

I hope this can be fixed, even though it is a very niche issue.