Custom Field is Required even though it is not assigned to any Screens

Steps to Replicate

1. Create a multi-select custom field but not assigned to any screens:
   
2. The options that are available for the custom fields are as follows (1 until 5). No default values are set:
   
3. Navigate to the Field Configuration and make it Required:
   
4. When you are creating a new issue, the following error will be displayed even though the custom field is not associated to the screen:
   

But, this behaviour is not consistent in JIRA. In other Workflow Transition, the issue can be transit even if the field is not associated to the screen. Steps to reproduce:

1. Create a new custom field
2. Map it to the Create Issue screen
3. Create a new issue, leave the custom field blank
4. Make the custom field as Required in the field configurations
5. Re-Index JIRA to make sure the new configuration does take effect on the issue
6. Try to resolve the issue, note that the field do not appear in the Resolve Issue screen, and that the issue can be resolved successfully without specifying the custom field value
   we also observe that the custom field will be required in the Resolve Issue transition if we map it to the Resolve Issue screen.