If you change the default order of payment gateways you get a jquery parse error at checkout and you can not select any payment method.
If you accept Credit Card, Sofortüberweisung and Paypal, the default order is Credit Card first, than Sofortüberweisung and the last one is Paypal. If you reorder the payment gateways and but Paypal and Sofortüberweisung above Credit Card, you will get the above issue.
The issue seems to be related to the SEPA additions in 11.3.
Kind regards
Michael