Put the summary of the bug you're having here
What I expected to happen was...:
I put down the bed, click it while riding the horse, and "wake up" to horse still alive to continue exploring.
What actually happened was...:
I was riding a horse while exploring since it was a new world, so I placed a bed while riding the horse and clicked on it while still on the horse to fall asleep due to it being nighttime, and after I woke up the horse was gone and no where to be found.
Steps to Reproduce:
1. Ride a horse and place a bed while it's nighttime
2. Click on the bed while still riding the horse