eZ\Publish\Core\FieldType\Time\Value::fromTimestamp uses setTimestamp while eZ\Publish\Core\FieldType\DateAndTime\Value::fromTimestamp uses new \DateTime("@{$timestamp}") which results in an inconsistent handling of these Field Types.

Consider the following PHP example:

$dateTime1 = new \DateTime("@3600");

$dateTime2 = new \DateTime;
$dateTime2->setTimestamp(3600);

var_dump($dateTime1->format('H:i:s'), $dateTime2->format('H:i:s'));

DateTime modified by setTimestamp takes into the account server timezone, while the one created with "@" format does not.