Even if not shown, date parameters always include a time. When an explicit time value is NOT present the time is 00:00. Additionally, values chosen using the date picker have a time of 00:00 by default. When using a date without a time, end date parameters should be set one day after the last day to include. For example, to run a report for the entirety of August 2017 the start date parameter value would be 8/1/2017 and the end date parameter would be 9/1/2017.

For many of the custom reports I created for CML, I have the end date be end of day for the date chosen to get around this problem.