When throwing bottles of enchanting the texture appears normal when first thrown. But, if you go to a distance where you can't see the orbs and come back sometimes they just appear as shadows. It seems that this only happens when in large amounts.

To recreate:

1. Throw a large amount of bottles on the ground below you while flying.
2. Fly up till the orbs go out of distance and you can't see them anymore.
3. Then while flying down the orbs will flash between the normal texture and the shadow. Sometimes, like in the picture I attached, they dissapear and leave the black shadow. Sometimes it may cause it to happen even more if you fly just above and cause the orbs to move towards you but not picking them up.