Yes. I experienced sleep paralysis for over 30 years chronically and could guarantee having an episode whilst on my back. Whereas, if I slept on my side or stomach there was less chance of it happening.
I can recall going to sleep on my side, only to wake up during an episode to find myself on my back. During sleep, I had rolled onto my back and witnessed the sleep paralysis episode whilst out of my body. I was also very much aware of my mistake whilst still sleeping.
I have experimented with this recently whilst lucid dreaming and realized that the energetic part of us that can leave the body, finds it easier to leave whilst we are on our back. It’s a little tricky to leave your body if you’re on your side, which is why it occurs more when you’re on your back.