TYPO3 Core

When using a \DateTimeImmutable property and TCA dbType is set to date, time or datetime then the actual value won't get persisted as UTC in the database.

After the value has been persisted, the value will be read from the database and interpreted as UTC, thus the model will have a wrong \DateTimeImmutable property value.

The issue is caused, by \TYPO3\CMS\Extbase\Persistence\Generic\Mapper\DataMapper::getPlainValue() where timezone will be set to UTC.
The \DateTimeImmutable won't be updated with the "new" timezone, thus a wrong value will be stored.

This issue occurs in the following TYPO3 CMS versions:

• v10.4 LTS https://github.com/TYPO3-CMS/extbase/blob/v10.4.18/Classes/Persistence/Generic/Mapper/DataMapper.php#L752
• v9.5 LTS https://github.com/TYPO3-CMS/extbase/blob/v9.5.28/Classes/Persistence/Generic/Mapper/DataMapper.php#L774
• v8.7 LTS https://github.com/TYPO3-CMS/extbase/blob/v8.7.32/Classes/Persistence/Generic/Mapper/DataMapper.php#L705
• v7.6 LTS https://github.com/TYPO3/typo3/blob/v7.6.32/typo3/sysext/extbase/Classes/Persistence/Generic/Mapper/DataMapper.php#L703

TYPO3 CMS v11 should not be affected, because the the timezone won't be altered.