[PS 1.7.7.3] Order confirmation impossible if total is 0 and "General Terms and Conditions" not required

[sanji_japan]

Hello,

I am facing an interesting situation in an (almost) not modified PS 1.7.7.3

When a customer has an order with a total of 0 - typically because he has money on his account coming on deduction to the purchase - and the shop is not requiring to validate "General Terms and Conditions of Sales", then the final checkout button is unusable. However, if I add mandatory "General Terms" to validate, then the order can go through without any issue...

I hope this is understandable. Has anyone see that behaviour?

Thanks,

sanji