Using _scheduleExpiratorEvent() and interface is broken

Using this code to set expiry on a WooCommerce product

$expire_date = '2020-10-01 00:00:00';
$ts = get_gmt_from_date($expire_date,'U');
$opts = array();
$opts['expireType'] = 'delete';
$opts['id'] = $result->id;
_scheduleExpiratorEvent($result->id, $ts, $opts);

When viewing the product in WordPress, Post Expirator panel shows 2020 January 01 and October is missing from the dropdown: https://imgur.com/a/Q4oBNVg

This means if the user saves the product without correcting the date fields on Post Expirator the post is deleted immedately.

I checked the postmeta and the timestamp is correct. I created a test product using the WordPress inteface and the postmeta is identical to the postmeta when set using PHP.

Any ideas?