I've noticed a minor issue some dropped items will hover slightly above the ground. I haven't tested everything, but they all seem to be items that have a 2d sprite, but can be placed in the world as a block. Saplings, seeds, carrots, potatoes, vines, flowers, double flowers, doors, signs, grass, rails, glass panes, iron bars, ladders, and probably several more items hover.

The cause of this is all of these items are actually an AliasedBlockItem

Solved

        // 0.01 barely brings flat items flush to the ground
        matrixStack.translate(0, 0, 0.01f);
        if(itemEntity.getStack().getItem() instanceof AliasedBlockItem) {

        } else if(itemEntity.getStack().getItem() instanceof BlockItem) {
            // make blocks flush with the ground
            matrixStack.translate(0, 0, -0.12f);
        }

Fixed in 1.2.3+ thanks to Skylortrexler.