Some easy stuff:

• wrong TOP name info
• Item z-fighting (I hope this is the right feature/thing/name :D )

Steps to Reproduce (including precondition)

Look at a Minecart and hold the Item in the hand an move the cam.

Screenshot of this Problem

The 3 red arrows shows the 3 points of z-fighting

Your Environment

• OS: Win10
• Full Forge version: 1.12.2 - 14.23.4.2749
• Mod version: MetalChests-v2.3.9.gb92ee2f
• Theoneprobe-1.12-1.4.23

(Yes, Optifine is installed, but I have the same fighting bug with the tinkers axe without Opti)

Can you double-check if it happens the on the chest cart item without optifine? The tinkers axe z-fighting is because of a different system it uses to generate textures which metalchests doesn't use.

Jep, without Opti, the same 3 pixels has the fighting.

That's normal for minecarts, yes. Just fixed the name display for minecart entities.