Ability to view a graph in a Monthly span only

I am coming up with a problem where i have some tags that are importing there Data via a script and when i graphe these tags i am only able to view them over the monthly span i.e. unable to see them in a weekly, daily or hourly span. Would you know what may be causing this, please note that i was able to see them in those spans up until about a week ago.

What changed?