Polterglitch

I have figured out what is happening. What is happening is my realm is loading the resource packs in the wrong order.  Making it load the faithless resource pack at the top instead of the bottom of the load order. I figured this out by removing faithless from the active resource packs and the other packs started showing in the world.

I have found a previous bug report that matches what I have discovered:

https://bugs.mojang.com/projects/REALMS/issues/REALMS-11128?filter=allopenissues

The best way I know of to reproduce accurately is with Faithless. But when swapping Faithless with other resource packs using the same load order I do still notice similar issues like the item textures still not changing and the mob textures/models not being what they are supposed to. Attached are pictures of what I mean; the single player picture is how it is supposed to look. The resource pack I used instead of Faithless in the pictures is "BlockPixel" also from the marketplace.

Realms Picture

Single Player Picture