I don't think it does because I have two versions on the same system and no problems. But if I was having problems with one or the other, I might consider uninstalling one.
Does it hurt to have 2 Vegas Pro programs on your computer?
Just two of them? I’ve had three-four on the same computer with no problem whatsoever. That is one of the beauties of Vegas, that various versions are independent of each other and do not interfere with each other.