Record doesn't show if selecting earlier date interval
I think the problem with you query is the use of aggregated functions: sum and count. Using group by category, subcategory  shows only rows with different category and subcategory values: only one row for each category and subcategory.

You can add comments column on your group by clause. Another option is to remove group by clause, sum and count functions, but this second option generates a result without aggregates values. 

I hope this helps

Miquel Boada