when having a piece of armour in you inventory, it will sometimes have the texture of a trimmed piece of armour if you have previously trimmed a different piece of armour. for example, if i trimmed a full set of netherite armour, and then got a full set of iron armour, untrimmed, it would sometimes have the texture of a trimmed piece of armour, even though not being trimmed, and looking normal whilst wearing it and put it on amour stands. this is just in the inventory.