FYI, I had this same problem with my 2007 HW258. Made the adjustment to the limit screw only to have the same problem again.
Last night I checked it out again and found the problem to be that one of the nuts on the end of my cable drum. (There are 2 nylon lock nuts on either end) The one had stripped threads and was not keeping the end plates on the drum together. I was actually having the wire rope slip down off the drum when lifting the top. It would make a loud popping noise when this happened. I replaced the nut with a jam nut and used some thread locker. I will keep an eye on it but it should be good.
I also found that my switch locking bolt was loose too. I tightened this down, but after reading the info on the link above realized that my switch disk was never contacting my lower limit, so I now need to adjust this.
So moral of the story is, if you are under there working on your upper limit adjustment, look for these and any other loose or broken parts.