Fishing rod appears briefly reeled in when in offhand and throwing splash potions

The fishing rod appears briefly like it's not cast when holding it in your offhand and throwing a splash potion.

What I expected to happen was....

The fishing rod would appear cast even if I threw a splash potion

What actually happened was....

A short time after I threw the potion, the fishing rod appeared reeled in

Steps to reproduce:

1. Hold a fishing rod in your offhand
2. Cast the fishing rod
3. Throw a splash or lingering potion
4. → The fishing rod appears reeled in for a short moment