Critical error submitting Gravity form containing wlt-pounds shortcode

This feature has worked well previously but this problem started today.

I have a Gravity form (client intake) that contains wlt-pounds and wlt-date in their respective custom CSS fields.

Upon submitting the form the following critical error occurs:

AH01071: Got error 'PHP message: PHP Fatal error:  Uncaught TypeError: array_sum(): Argument #1 ($array) must be of type array, bool given in /clientsite-www/wp-content/plugins/weight-loss-tracker/includes/functions.php:833\nStack trace:\n#0 /clientsite-www/wp-content/plugins/weight-loss-tracker/includes/functions.php(833): array_sum(false)\n#1 /clientsite-www/wp-content/plugins/weight-loss-tracker/pro-features/hook-gravity-forms.php(168): ws_ls_iso_date_valid('2024-07-09')\n#2 /clientsite-www/wp-includes/class-wp-hook.php(326): ws_ls_gravity_forms_process(Array, Array)\n#3 /clientsite-www/wp-includes/class-wp-hook.php(348): WP_Hook->apply_filters('', Array)\n#4 /clientsite-www/wp-includes/plugin.php(517): WP_Hook->do_action(Array)\n#5 /clientsite-www/wp-content/plugins/gravityforms/gravityforms.php(7076): do_action('gform_after_sub...', Array, Array, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL)\n#6 /clientsite-www/wp-content/plugins/gravityforms/form_display.php(209): gf_do_action('gform_after_sub...', Array, Array)\n#7 /...'

The form submits, but the critical error message appears prior to the page redirect. I have not made any recent changes to this form

My web host has reviewed the error log and referred me to the plugin developer.

Thanks for any assistance!