When a minDate and maxDate are set for a datepicker dialog field in AEM Touch UI, in certain cases it does not allow to view the last month of the date range.
In this case, you are able to view the month of April and select April 1 or 2. However, the datepicker fails to allow you to click to view April 2018.
This bug is fixed in AEM6.4 and AEM6.3 SP2.
An overlay fixes package date-picker-month-range-fix-1.0.zip is attached to help work around this issue in AEM 6.3.