Problems creating DNS TXT via JSON API (let's encrypt DNS Challenge via nginx proxy manager)

I have tried to add a wildcard let's encrypt via nginx proxy manager using it's ISPConfig DNS Challenge plugin but was failing with this error:

API response with an error: Incorrect datetime value: '' for column `dbispconfig`.`dns_rr`.`stamp` at row 1 INSERT INTO `dns_rr` (`server_id`, `zone`, `name`, `type`, `data`, `ttl`, `active`, `stamp`, `serial`, `sys_userid`, `sys_groupid`, `sys_perm_user`, `sys_perm_group`, `sys_perm_other`) VALUES ('1', '2', '_acme-challenge', 'TXT', 'asdfg', '60', 'Y', '', '0', '1', '1', 'riud', 'riud', '')

I started to dig around and came across the function dns_rr_add where it loads the dns_txt.tform.php but this seems to have a default of ''

                'stamp' => array (
                        'datatype' => 'VARCHAR',
                        'formtype' => 'TEXT',
                        'default' => '',
                        'value'  => '',
                        'width'  => '30',
                        'maxlength' => '255'
                ),

I removed this default value in the hope it would not send any defaults and hence use the database default of the current timestamp which worked. I'm not sure if this is a ispconfig issue or rather something that should be fixed on API side.