Reports on "last month"

I have a bunch of scheduled reports sent to me each month and the reports use the "Last Month" option. But each report when sent to me includes the last day of the previous month as well. This is happening running reports manually as well. When I pick "Last Month" the dates in the picker will show 1st - end of month, but when I run the report I get last day of previous month, plus all days of last month.


Current report I ran:

Passport Cumulative Usage
Date Range: Last Month
start date: 4/1/2015 (auto set)
end date: 4/30/2015 (auto set)
include weekends checked on

Run the report and I get:

From: 3/31/2015 To: 4/30/2015