Sorry to bump this slightly old thread, although I've experienced some of the same, but more like whole aspects of the website not appearing.
This happened when my computer broke and I did send it back for warrenty, and therefore used a computer which hasn't been used for a good year time.
I updated everything, all from security to Java, to Firefox (The browser I use on both computers), and windows itself, well, everything.
I cleaned the browser data, temp files etc. a couple of times etc.
Well, basically one big swoop of cleanup & updates on all aspects in the machine, and yet it still happened.
If you ask my opinion, I think it's related in how well the computer is able to speak with the routor/modem in ones house, for example a rundown OS system and driver issues might make it loose some packages, and therefore break the load from
www.mangahelpers.com
Heavy websites like this, with a lot of scripts and what not to load, will probably have some issues with a bad communication with a routor/modem.
Never saw any light of any half loaded mangahelper website when I got my other computer back from broken hardware warrenty, so yeah, there's that, I suspect driver issues.
But who knows, it's not an area I have focussed on for many years, so I'm only suspecting.