Automation: "Edit issue" to add values to multi-select fields not working
tl;dr: Advice needed on why I don't have the ability to add values to multi-select fields rather than overwrite them when using Jira automation.
Background
I have created a new rule that when an issue is created inside an epic, the issue should check if the epic has been tagged with a specific component (ex: Engineering). If that's true, then the child issue should also be tagged with that component. That works well, but based on the standard functionality of automation, it overwrites the new issue's components completely, not adding to them.
For example: The epic was just associated with one component, "engineering." When I created the new issue I tagged it as "design," but didn't add "engineering" to the components field to test the automation. The automation then overwrote the components field to just say "engineering," rather than "design, engineering." That part, according to Atlassian documentation, is working as intended because I didn't ask it to add the component, so it overwrote it.
Issue
I want the epic's component to be added to the issue's component list, not overwrite any other components the issue was already tagged with upon creation. The documentation has steps for this, called "adding values to multi-select fields." It should work in theory, but I don't have the ability to do what the instructions say.
Instead, in my version of Jira, if I use the "copy from issue" function (called "Add components from current issue"), I lose the ability to add anything else to the field. So I can't add a second component like the instructions state I should be able to. Screenshot attached of what I see.
Theory
I had an inkling it had to do with how our Components field itself was set-up, but it's already set up to be a multi-select, here is how a ticket I have is tagged:
Any thoughts on why I can't do what the documentation noted?