Hi,
I had the same problem. My solution is to edit the "templates/checkout/_partials/steps/payment.tpl" and remove the class of the label tag which triggers the modal window.
Now I've inserted my own label instead of the "$condition nofilter" value, but if you have no language selection you can just add a normal html link here.
<div class="condition-label"> <label for="conditions_to_approve[{$condition_name}]"> {l s='agree to the terms of service' d='Shop.Theme.Checkout'} </label> </div>