In what scenarios could the use of substr() function in the script lead to errors or unexpected behavior when handling dates in PHP?

Using the substr() function to manipulate dates in PHP can lead to errors or unexpected behavior when the date format changes or when dealing with different time zones. To avoid these issues, it's recommended to use built-in PHP date functions like date_create() and date_format() to handle date manipulation in a more reliable and consistent way.

// Example of using date_create() and date_format() to handle dates in PHP
$dateString = "2022-12-31";
$date = date_create($dateString);
$formattedDate = date_format($date, 'Y-m-d');
echo $formattedDate;