If a banner is behind a Nether Portal and you look through the Nether Portal, the banner still shows as if the Nether Portal isn't there without a purple gloss from the portal or any distortion from the portal swirls.

Here is a link to a video showing what I mean: https://mega.nz/file/4QgCgAKD#2Axy8UjHXvnJi-dS971ut6orc2ym4LXUQAZdQP4IOUw

Steps to Reproduce:

1. Build a Nether Portal, preferably in the center of a room.
2. Place banners throughout the room you built the Nether Portal in.
3. Look through the Nether Portal at the Banners

Observed Results:

Banners appear normal and unaffected by any interference as if the Nether Portal is not present.

Expected Results:

Banners like all other mobs, blocks, etc. should appear distorted from the portal swirl when looking through a Nether Portal as well as have a purple tint applied to them from the Nether Portal itself.