I was just shift-clicking my inventory and accidentally placed tipped arrow on my off-hand slot with no other arrows in my inventory.

I tried shooting it with an infinity bow and it doesn't seem to work as the way it is suppose to.

The result I thought that will happen:

• Tipped arrow disappears from your off-hand as the bow (with infinity enchantment) shoots it.

The result:

• Tipped arrow stays in your off-hand and infinity bow shoots normal arrows instead.

To reproduce:

1. Grab a bow with infinity on it.
2. Place a tipped arrow (single) on your off-hand.
3. Shoot.

Happens in realms as well.

Edit:

Happens on Windows 10 as well: Bug video for Windows 10 verison