Cache is deleting too often

I can′t find out why this is happening, I disabled preload, and also tried to set cache timeout to 86400 seconds and scheduled it once a week at midnight.

But the cache is deleting itself probably every two hours I can′t find out why, there are not too much visitors on site, so there is huge possibility that person, who visit the site will see uncached version almost everytime. That doesn′t make sense to have cache then.

Thank you.