Line Chart changing back to vertical dots everyday if the date setting isn't re-setted everyday

[katto_16]

I have this line chart that shows the trend of the top 5 descriptions (Top N, of the count of description) within the span of past 3months, which I set the date filter to Relative date -> 3 calendar months. The date hierachy is Year, Quarter and Month. It looks something like this.

However, on the following day, it will automatically change back to vertical dots unless, I change the date to date, then change back to date hierarchy, and remove Day as I wanted. Then it'll go back to the lines. It has been this way for a few days. I'm not sure what the problem is. 

The source is SQL server for one of them. Another one with the same problem is connected straight to the source PC's data log.

Any help is appreciated. Thanks.