Throws error on non-repo plugins

I’ve been getting this notice for a while:

Notice: Trying to get property of non-object in public\wp-content\plugins\my-wp-health-check\php\class-wphc-checks.php on line 189

Which is this line:

if ( time() - ( 60 * 60 * 24 * 365 * 2 ) > strtotime( $plugin_info->last_updated ) ) {

I got around to looking into it today, it’s happening on ‘advanced-custom-fields-pro’.

The call above to get the plugin details returns a serailised NULL ( N; ) so unserialize is returning null.

I think a check could be added in that case, perhaps with a warning that the plugin status could not be checked.