OK, so given that it loads after refreshing the page, it's probably not a security issue on this website. I doubt it's anything on this website. It's more likely the end-user's machine, their ISP, the timing it takes to get replies to requests for pages from the server, IP issues with their ISP's and the DNS that they use, etc.... stuff like that. I recall reading something about TBN changing their IPs or DNS or something like that recently, and it seems the problems have come up since then, and only for some users. There are many, like myself, who have not seen these issues. That's why I don't lean towards it being an issue with this website. I'd guess that the end users are getting conflicting IP and DNS info from different places different times from their ISPs, thus causing confusion on their machines.
Not at a PC today, so can't investigate myself. Ipad doesn't do well with network diagnostics.