Is there a max amount of times I can rest to get random battles?

I have been consistently getting a message about being startled awake but there is nothing around. I am getting this message after hours in the same location camping.

so is there a check or cap on random encounters?

thanks

Actually you can pretty much count on being awakened by a gang of enemies whenever you sleep more than 4 hours (especially at night). Don't know what you mean by "nothing around." In all of my many, many play-throughs there is always someone trying to take my head off when I am awakened.