Hi Edosky.

I ended up logging a ticket with ServiceNow and they confirmed it's linked to a known bug with the parallel action that is meant to be fixed in Xanadu. I'm currently weighing up when to upgrade (currently on Washington DC), but the description of what you're seeing worries me a bit! Sounds like you may also need to log a ticket - I'd be keen to hear the outcome of your issue as a lot of our flows use this function. 

The workaround for us until we upgrade is to log a ticket with ServiceNow any time we create a new workflow with this function and then again when we push it from development to production. Copying a workflow with the fix applied to create a new flow does not work either - it has to be done for each flow sadly.

Hope this is helpful,

Anna