phprunner 10.3 - Dates changed from 0000-00-00 to empty string?

A quick update -
This is happening AFTER the "Before Record Update" event -
As a test - I set the date field in the Before Record Update event:
$values['CP_DOB'] = '0000-00-00';
Somewhere after this event, PHPRUNNER 10.3 is changing the value of this date field to NULL before the mysql database record is written?
If I set CP_DOB to a different "non-dummy" value in the Before Record Update event all works fine:
$values['CP_DOB'] = '2020-04-17'; (this works)
Thanks again for your help -

Just ran debug and confirmed based on the generated SQL that on the edit page, PHPRUNNER 10.3 is changing date fields that are stored in mysql as 0000-00-00 to null which bombs upon SAVE when it tries to update the field in mysql with the null value (these date fields are NOT set to accept null values).
I suspect there's date validation code that's taking the 0000-00-00 dates and changing them null as part of failing validation? Is there a way to override this?

Just ran debug and confirmed based on the generated SQL that on the edit page, PHPRUNNER 10.3 is changing date fields that are stored in mysql as 0000-00-00 to null which bombs upon SAVE when it tries to update the field in mysql with the null value (these date fields are NOT set to accept null values).
I suspect there's date validation code that's taking the 0000-00-00 dates and changing them null as part of failing validation? Is there a way to override this?

I went ahead and converted all of the date fields to accept null values with a default of null and that has resolved the issue