I am trying to edit an automation but Support is not letting me save the changes and I receive the following error:
You are receiving this error message because the changes made to your automation do not have a nullifying condition telling the automation when to stop running. You could fix this one of two ways:
Modify the automation to include a nullifying condition
The error message, itself, gives you an example of a way you can setup a nullifying condition. If one of the actions is "Priority is Urgent", then make the nullifying condition, "Priority is High".
This support article provides you with another option to create a nullifying condition with tags, ensuring the automation only runs once.
Create a trigger instead
Often times, this error presents because you are setting up an automation to take an action that would be better accomplished by a trigger. If the conditions in your automation are not time-based, create a trigger instead.
To understand the differences between automations and triggers, see Automations vs. Triggers - When To Use What Follow.