Fatal Error With Version 3.6

Version 3.6 of this plugin causes a fatal error to occur in the WooCommerce checkout form (i.e., a critical error occurs when clicking/tapping on the shopping cart checkout button). My debug.log shows the following: PHP Fatal error: Uncaught TypeError: number_format(): Argument #1 ($num) must be of type float, string given in /xxxx/xxxx/public_html/wp-content/plugins/woo-donations/woo-donations.php:235

After downgrading to 3.5 the plugin appears to work fine.