Check out not ok when only one payment method

[warp-it]

Prestashop 1.7.8.2
If you only have one payment method (Bank Wire) the round radio button ('Zahlung per Überweisung' in screenshot) is blue / selected, but the button PLACE ORDER (BESTELLEN in screenshot) is gray and mouse over gives a forbidden sign. Clicking on the radio button doesn't change anything.

Nevertheless you can click on PLACE ORDER and it works.

Screenshot-1

If you add a second payment method, both radio buttons are white. After selecting a payment method the PLACE ORDER button is no longer gray, and works as designed.

ScreenShot-2
ScreenShot-3

I found an article, where it is advised to change a TPL file:
https://github.com/PrestaShop/PrestaShop/pull/21654/files/58878162576eb30dc4a72e8075359a1bb42fd7bd
I'm not sure, if this is related to my problem, Anyway, I had the second version already. Changing back to the first / old version didn't change anything.

What has to be done to get the PLACE ORDER button work as designed, with only on payment method?

Regards
Heinrich

[warp-it]

24 minutes ago, ndiaga said:

If   you  have  only   one  payment  method  that  method  should  be  selected  by  default.
Is   that  method   for   all  customers?

It is selected by default, but the PLACE ORDER BUTTON stays gray.
The question concernig 'all customers' is not relevant, because the problem is gone, as sooon you have more than 1 payment method.

[warp-it]

Problem can be reproduced in demo.prestashop.com.

As soon as you disable 'Terms of service' under 'Order settings' and only one payment method is active, PLACE ORDER button in checkout doesn't work as designed (stays gray = inactive)