Time schedule of posts not working properly

[fredk]

Don't know what other term to use for this

I keep two windows open;

1 for Unread Posts and 1 for All Activity

I have set Unread Posts for the last 4 weeks but it often only goes to 12 or 16 hours past. 

If I go and choose 4 weeks again only then will it show the older posts.

This affects All Activity and restricts it to only the last day, until I choose 4 weeks on Unread again