Why in Dashboard view the date filter (DD/MM/YYYY) only accepts day numbers < 20?

Question

The same problem occurs also in Dashboard Configuration view, where we can set a predefined date filter to the dashboard. The calculation logic connected to the dashboard uses this groovy element:

api.dateTimeUserEntry("Date")

Answer

This looks like a bug, so I have reported it to Engineering. The JIRA ID is PFCD-2651.