Can't focus to infinity with my 135mm f/2L!!!

This is an old thread, but it is the only one I have found with a similar problem to the one I am having with this lens. Actually, the same exact problem as described by the original poster.

I am hoping to hear how the issue was resolved, if at all.

A few days ago I was out with my camera taking pictures, when I noticed my 135 2.0 was not focusing at infinity. Came back home and started playing with it, and the lens will not focus from my 4th floor apartment down to the sidewalk across the street and beyond. Doesn't matter if I use AF or MF, distant objects are never in focus. The lens doesn't hunt for focus while on AF, it just goes to infinity and stops, I don't get focus confirmation from the camera. Or I can manually focus it, and infinity is still always out of focus.

I noticed the problem on a 5D markII, and tested it on a 40D and a rebel xti, same results on all camera bodies. Cleaned the contacts and mount, but that didn't help

The lens works just fine at close range, it doesn't make any weird sounds and still focuses as fast as it did before. there is no indication that it is malfunctioning whatsoever, until I try to focus on far objects. The distance scale has not changed neither, I can reach the infinity mark on the distance scale (AF or MF) and manually turning the ring is smooth as it has always been. I don't have the exact working distance, but as I mentioned before, it will not focus on the sidewalk across the street from a 4th floor apartment.

The last time I used the lens was 5 days before I noticed the problem and I took several shots at infinity, and it was fine then. The lens had been sitting in my camera bag in my closet, as it has been for like 6-7 years when not in use. What bothers me is, I don't even use it that much. I only use it once in a while and it is the only lens I had problems with.