Blanks area area in posts

Hi

Every few pages I see a black area. In other words I have missing posts at 8 and most of the time it shows 8 but every few clicks it only shows 7 posts. This is strange as I have 2900 posts so there are more than enough to fit.

I am running 4.2.2

George

https://ww.wp.xz.cn/plugins/yet-another-related-posts-plugin/