Urgent fix issue with Custom Payment Gateways for WooCommerce

I have the following plugin installed - (woocommerce/wordpress) Custom Payment Gateways for WooCommerce Pro
When a custom gateway is used you can set the status order status it goes too.
This was working fine until I updated everything (not this plugin) now it works but all orders default to processing rather than the order status it is set to.
I have the old website where it worked and the new website where it doesn't

I have 'WooCommerce Order Status Manager' installed too, when this plugin is disabled and I set the custom checkout to a core status it works. When the plugin is enabled and I set it to a core status it doesn't.
I have tried downgrading the 'WooCommerce Order Status Manager' plugin to the last version that worked on the updated website but it didn't fix the problem.

Evidence suggests there is a potential conflict with these two plugins.
The answer may be in the free version of the plugin that has been updated recently where the pro plugin hasn't
wordpress.org/plugins/custom-payment-gateways-woocommerce/#developers

Can you fix this problem and how quickly can you do it, this is the last bug before I transfer this website to go live and I need it to go live asap.

Happy to work hourly if you prefer, I just did a fixed budget as a starting point.