Hier das Zitat, ggf hilft es wem:
When PayPal Plus is used on its own as the only payment plugin the following happens
VM 3.6.0 works correctly
VM 3.6.1 will fail
When PayPal Plus is used together with other payment plugins such as klarna or Sofort, the opposite happens
VM 3.6.0 will fail
VM 3.6.1 works correctly
VM 3.4.2 will work for all combinations
You can either change to VM 3.6.1 or wait until a fix is released.
-stand September 2019.