DB manager save changes creates invalid change

Wappler Version : 4 beta 1
Operating System : mac big sur
Server Model: node
Database Type: maria
Hosting Type: custom

Expected behavior

When a table has a datetime field, it should be null if not set

Actual behavior

It is set as an empty string

How to reproduce

Using a table with a datetime column, the calendar selector pops up immediately after pressing Add New:

Screen Shot 2021-05-14 at 8.24.31 AM1810×832 63.2 KB

If I do not select anything in the calendar, and provide other data and click Save Changes, the following error is produced when attempting to apply the change:

Screen Shot 2021-05-14 at 8.25.21 AM932×472 49 KB

The migration file that results shows created_at being set to an empty string, when it should not be set at all:

exports.up = function(knex) {
  return knex('app_settings').insert({"created_at":"","key":"test","value":"data"})
};

exports.down = function(knex) {
};