Make a texture (512x512) and when holding it in your hand it's 32x larger than the texture should be. Tested this with other textures (in screenshots) all scaled 128x to 1024x including 512x and was not able to recreate this. I have attached also the texture pack with which I attempted to recreate this bug and in it is also the retextured wait music disc that is way too large.

screenshots:
shard is 1024x
armorstand is 256x
golden apple 128x
regular apple 512x

with all these i couldn't receate