When running the Field optimizer functionality, if the custom field is used and there are values defined in this field, the Optimizer will identify the field is used by X project and when we click on 'Change context', it adds the relevant project context to it.

However, if the custom field was not in use, the Optimizer will identify the field is used by 0 projects and when we click on 'Change context', it removes the context from this custom field, which can cause fields to be hidden.

It would be good to have the option presented to the Jira admin when such a situation occurs.