Featured post included in content area while switched off

Extra information: screenshot from the setting in Theme Options > Blog, show featured posts in the slider AND the content below is switched of, therefor I don’t understand why the featured post is also shown in the feed below.

Hi Khunchay. Can you post a link to your site? Thanks.

It’s this site

Do you have Featured Post Count set to 1? Do you have a Featured Category selected?
How about this – what happens if you check the “Include featured posts…” option and Save Changes, then uncheck it and Save Changes. Is it still displayed in the content area?

Featured Post Count set to 1: yes

check the “Include featured posts…” option: tried that before, no result

Featured Category selected: Hmm… when selecting the same category the clone post indeed disappears. Just don’t understand why, this solution looks like ‘not normal’. Also it’s weird to for every new post (of another category) having to change this settings.

On my other website there is no ‘featured category’ selected and never get double posts like this.

“Not normal” for sure. If that box isn’t checked, the Featured Posts should not be included in the content area, regardless of how many there are or whether or not you’ve selected a Featured Category. Sound like your second site is working correctly. It might be a plugin somehow interfering with the pre_get_posts function. You might try deactivating all your plugins and see if that makes any difference. If it does, then reactivate them one at a time and see which one causes the problem. Other than that you might try reinstalling the theme. Don’t know if that will fix it but not sure what else to try.