Yeah It's quite a common thing to happen with V shaped guitars.
I think it's because the balance is off with the body being a counter weight to the neck, and the strap buttons being in non balance point.
I have a King V and I just wrap the strap around the front of the top horn not around the back. Which not only holds the guitar at an angle that goes bottom out so I can see the front easier, it's also easier to hold the neck up than it would be without. I also rest the lower horn on my hip so it's sorta in place all the time.
Example: