pop up window without content 'do you want to download index.html'

[woodencoffeetable]

as above & see screen shot.
to do with adverts?

Hi, OP

Thanks for flagging this. How strange (and annoying!).

Thanks for the screenshot. Would you be able to let us know the device you are using? Also, if this just happens on one thread, could you let us know which thread it is?

apple tablet/phone (happening on both)
various threads. the top screenshot was from the 'computer says no' thread.

Hi OP,

Can you try closing all your tabs and trying it on its own page, see if the problem persists?