Cold Weat Version: v2.2.1 (newest build)
Forge Version: 47.2.0
Optfine Version: I6 pre6
Log & Error Output: None

It just looks like this:

It looks like Optifine is doing some kind of weird squashing to the armor texture. I tried with a square texture (128x128) and it had a similar effect. I also tried another mod that adds 3D armor models, and the same thing happens.
Considering Optifine can't even load into a world unless you use the previews, I'd say it's in a pretty rough state at the moment. It's very likely their issue.

I'd honestly suggest you just move to a Sodium port for now (like Rubidium, Embeddium, etc.). These mods are built on a much more modern framework and often don't have these random compatibility issues that Optifine is now infamous for. I will be closing this issue because it seems pretty open-and-shut to me.