It looks like vBSEO is not doing enough QA before releasing a new version.
Well, I am <em>glad</em> to see it isn’t just me! And yes, it is not only intermittent, but it may happen on one page of a thread but not another. In fact, when I tried to post this post, I could access page one of this thread, but not page 2. I guess its like going to the Dr and the symptoms being gone when you walk in the door, only to return as soon as you leave…
I also have jym’s symptom (the xcache_isset error messages) on a Mac with Safari.
This issue is resolved.