Discount settings not saving

Hi guys, love the plugin, it’s perfect for the site I’m building.

Just one thing that’s not working though, I’m trying to add a discount and noticed that when I try to name the discount and choose to add the extra’s price in the calculation, it’s not saving my choice. When I refresh it’s reverted back to the default settings.

I don’t know if it’s just me or not.

Thank you for any support.

https://wordpress.org/plugins/booking-system/