Lately one of my sites has randomly started to serve some pages in https. The problem goes away temporarily if the "clear cache" button is used. But it is only a matter of time when the same problem returns.
I found another guy describing the exact same problem in this forum, which hasnt any answers yet.
We use "https" for administration in the WordPress Admin Panel. I see how this problem might be related to that. But it worked well for the first month, so I dont know what is making this happen now all of a sudden.
I by the way have an exact replica of this site, but in another language - and there the problem doesnt appear, which makes this even more strange to me.