Timeline slicer - 8 days on Week 5 of 2016?

As the title says W5 of 2016 seems to have 8 days on timeline slicer, beginning from Jan 31st and ending at Feb 7th :

I really need each week to have only 7 days, W6 beginning at Feb 7th instead of 8th. Is there any way to change this? Anyone else having this problem?

Thanks!