TYPO3 Core

I made an extension for a listing with some birthdays.
I used the kickstarter to create the main extension and especially the field type "Date" for saving the birthday.

It worked fine - until I realised, that some dates where not correct saved into the DB. Normally the timestamp gives back the date - hour and minute should be 0.
But some timestamps do not save the correct time, because they save one hour less than it was filled into the form. It appears, that these dates are randomly.
for example:
i fill 30-10-2006 into the form and it is saved as 30.10.2006 00:00 h
i fill 30-10-1988 into the form and it´s saved as 29.10.1988 23:00 h

The errors occured with 4.0.0 and 4.0.1
other versions weren´t tested
(issue imported from #M4159)