Sounds like a PSE problem to me, I would ask the question in the PSE forum.
But maybe a work-around is to do a normal Save in PSE (not Save for Web), and then the edited photo should appear in Lightroom, and you can do the equivalent of a "Save for Web" using Lightroom (in the Export dialog box, check Resize to Fit and enter the desired size)
There is no OSX of 10.9.9. I have the latest which was just updated a few days ago and it is 10.9.5
oops, you're correct. I have 10.9.5 - regardless I'm still having the issue between LR5 and PSE13.