In the Automation -> Auto Acknowledge
Editing the Pattern Testing list to include a new pattern the save option doesn't appear.
After editing the Pattern Testing list, under the Auto Acknowledge I unchecked Always respond via Direct Message, and then the Save changes to Auto Acknowledge appears.
I clicked save and changed away from Automation and back to Automation.

Always respond via Direct Message is now unchecked, but my changes to Pattern Testing are not there.

Summary:
Changing Pattern Testing gives no option to save, nor is able to retain changes.