Occasionally I'm getting "Waiting for available socket" when trying to load maths heavy pages like https://en.wikipedia.org/wiki/Revision_theory. The wait can last for several minutes, a reload seems to cure the problem.

I'm using Chrome on a Mac. I'm not sure if its relevant but it seem to occur infrequently viewed pages which are listed in the https://en.wikipedia.org/wiki/Category:Articles_with_math_errors due to prior restbase errors.