[Mac, Robot] DatePicker calendar popup is not shown on second click using robot

The date picker calendar popup is not displayed when clicked using robot for second time.
The issue is observed only on Mac, with both old and new implementation of robot.
Attaching test programs:
1. Old robot : DatePickerOldRobotTest.java
2. New robot [JDK-8090763] : DatePickerRobotTest.java

Steps: [Line: DatePickerRobotTest.java]
1. Click DatePicker to show calendar popup. [Line:61]
2. Select date from calendar popup. [Line:64]
3. Repeat 1 -> This does not show calendar popup. [Line:66]
4. Repeat 2 -> Does not work as 3 failed. [Line:69]

Another way to observe the issue:
1. Comment line 66 to 69
2. Execute the program
3. Manually click once on DatePicker, calendar popup does not get displayed.
4. Click again manually on DatePicker, calendar popup gets displayed.

If all the above steps are performed manually using mouse then issue does not happen.