DateTime & DateTimePicker validation problems

Hi all, during my work with DateTimePicker I had validation problems. When the user chooses a date from the popup calendar all is fine, and validation works fine when the field is empty, but when a user chooses a date like 30.1.2021 from the calendar(current pattern Locale.GERMANY) and after manual editing, he writes the date like this 31/11/2019, validation didn’t show that something wrong with date, will be saved last valid value in the date picker. I also find some track issues in github for this bug. But, how can I use safely the date picker now in my app? All I did, is disable the date input field with js, this seems not a good solution, but I can’t found another way to avoid the validation issues. TimePicker doesn’t have such problems, all fine with it.

I discovered that when I use this picker in polymer template it works fine, html and java piker versions have different validation.