Getting Error from Defender

Hi Team,

I just checked my Error messages via my New Relic console (third party service) and see over 200 errors coming from Defender, starting yesterday, and still happening, probably because it's scanning my server right now.

The error is as follows:
Uncaught exception 'Error' with message 'Call to undefined function get_core_checksums()' in /var/www/vhosts/martinbaileyphotography.com/httpdocs/wp-content/plugins/wp-defender/app/module/scan-module/component/class-wd-scan-api.php:205

And here is the stack trace:
in WD_Scan_Api::download_md5_files called at /var/www/vhosts/martinbaileyphotography.com/httpdocs/wp-content/plugins/wp-defender/app/module/scan-module/component/class-wd-core-integrity-scan.php (153)
in WD_Core_Integrity_Scan::scan_a_file called at /var/www/vhosts/martinbaileyphotography.com/httpdocs/wp-content/plugins/wp-defender/app/module/scan-module/component/class-wd-core-integrity-scan.php (88)
in WD_Core_Integrity_Scan::process called at /var/www/vhosts/martinbaileyphotography.com/httpdocs/wp-content/plugins/wp-defender/app/module/scan-module/controller/class-wd-scan-controller.php (359)
in WD_Scan_Controller::process_a_scan called at /var/www/vhosts/martinbaileyphotography.com/httpdocs/wp-includes/plugin.php (600)
in do_action_ref_array called at /var/www/vhosts/martinbaileyphotography.com/httpdocs/wp-cron.php (117)

This error did not happen last week. It started this week, and PHP was updated automatically updated to 7.0.10 this week, from 7.0.9, so that may be related.