Sorry for the delay, all - thought I turned on notifications for this thread, turns out I didn't.
Super smart idea to impersonate the user - I did that and didn't notice any of the errors he was saying he was finding, so I am surmising that this is indeed on his end. He is the only user posting this, so I'll work with him on javascript. He said he cleared the cache, but I can walk him through that to ensure he actually did.
