Spyglass disappears when swapping hands in a very specific way

Doing what I did in my attachment causes telescope to vanish.

How to reproduce:

1. Use offhand key to put a spyglass into your off hand
2. Use hotbar key to put a sword into your hotbar slot
3. Exit the inventory, and press F1 first.
4. Go into third person view.
5. Hold down right click.
6. Swap offhand.
Result: The spyglass disappears.