Custom Fields and Automation Rules

I'm wondering if anyone has been successful using Custom Fields in Conditions and/or Actions while creating Automation Rules. I'll briefly explain my goal/intention for the Automation Rule, then explain the issue I'm running into.

After a user fills out an Incident form, based on the selection of two fields (Priority and a Custom Field #1 we created), we want to automatically set the value of hidden Custom Field #2 that we created. This will require a number of Automation Rules in order to account for the various combinations of Priority and Custom Field #1, but I understand how to create those.

The issue I'm running into is the fields that the Automation Rule presents to me. I seem to be obtaining a list of Custom Fields that do not belong to our organization. While creating a new Automation Rule, I can refresh the page numerous times, receiving different options in the Fields dropdown (for both Conditions and Actions) on each refresh. This means that most of the time, our organization's Custom Fields are not available to select in these dropdown.

The other way this issue manifests is when viewing the list of previously created Automation Rules. In the cases I was successful receiving the correct list of custom fields, and therefore able to select the correct field in the Action, it then displays a message that the Custom Field has been deleted. This is not the case, as I can verify that the selected field is still active. However, since it's returning fields that do not belong to us, it assumes the selected field is not a viable option.

These are the calls that are returning the incorrect field lists: