Hi Mark,
There is a known issue that when a filed is deleted from a function that is pre-added to a playbook, you will see the exact error when you try to save the playbook again.
The workaround is: in the playbook, edit the fields of the problematic function (e.g., modify one of the static value) or, remove and re-add the function, then you should be able to save the playbook. Sorry for the inconvenience it will be fixed in the next release.
Thanks.
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Gilbert Liao
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