Summary

Even when you restrict a field to an issue type through field context, it's still selectable by other issue types when viewing the plan.

Context

If you create and restrict specific fields (e.g. 3) to be only visible by initiatives, epics, and tasks, respectively, they are still selectable by any issue type in the plan view. This can cause confusion, mainly for text fields as they will still hold value on the plan view, but will throw an error when you commit the changes.

In the example above, "Business Benefit" is restricted to the Initiative issue type, but can still be selected by Epics and any other issue type.

Suggestion

Make unavailable fields not selectable to that issue type in the plan view.