Report data changes after publishing

Hi,
I have problem when publishing one report recently. It's a report that i used to edit and publish multiple times but never incountered a problem until now.
So i have a histogram that displays stock value per date. Every Bar of the histogram displays the stock value of each day (December and january).
But lately when i publish the report the stock value of 31/12 adds up to the value of 01/01 and the bar that's supposed to contain the stock value of the 31 decemeber dissapears.
No matter how many changes i apply to the repport the histogram looks all good on PBI Desktop but once i publish it the 31/12 Bar dissapears and takes place it the 01/01.