“February 29”, also known as “leap day” or leap year day.
If monitoring start from leap day (Feb.29), User can’t checking past data on end of March (Mar.30, 31)

Step to Reproduce:
1. Create Item and contain history from Feb.29, 2016
2. Set the clock - Mar.30 or Mar.31 (Client)
3. Monitoring -> Latest data -> History or Graph - open Item details page (history.php)
(Reproduce must be used with item ‘history’. If you set item type use ‘Numeric’, You need to set change to ’Trend storage period’ - 0.)

In this case, I confirmed Zoom module’s starttime was “Mar.29”. and April 1 is fine.
This problem is affected by client side’s clock. so this is frontend problem and can be considered a cause javascript.

Please check the attached file.
(Left : 3/31, Right : 4/1. and SQL Results)

+ Additional information
I checked and confirmed that there are more problems with some other days.
and this issue’s continue to occur for a long time after March.
So, I decided to change priority with this issue.

Please see the comments below :