Error changing catagory

[Grover-D]

When I make any change (or none at all) and submit the change (or no change), I get:

Error

Invalid color: "000000"
Backtrace

#0 /var/www/htdocs/php-calendar-master/src/category_submit.php(50): soft_error('Invalid color: ...')
#1 /var/www/htdocs/php-calendar-master/src/calendar.php(872): category_submit()
#2 /var/www/htdocs/php-calendar-master/src/calendar.php(801): do_action()
#3 /var/www/htdocs/php-calendar-master/index.php(73): display_phpc()
#4 {main}

If I fill in the color manually, it does the same thing.

If I first go to the color palette it seems to work.

Latest version of php-calendar/php-8.1.12/apache 2.4.56-1/MariaDB 10.4.26-1