Issue Summary

Using the Custom field User Picker (single user), you can be able to add a user to this field to serve for various use-cases. However due to this bug, once set, the value can't be cleared. it can only be changed to another user.

Steps to Reproduce

1. Create a Custom field of User Picker (single user) Type
2. Add this field to the Screen
3. Create an Issue and add a user to this field
4. Try to clear the value and update the issue again.
5. refresh the page and noticed the user isn't cleared.

Expected Results

• Once you've cleared the value, the user that was there before should be cleared and the field should be blank.

Actual Results

• The Field cannot be cleared, it can only be changed to another value.

  VIDEO DEMO
  fields.mov

The below exception is thrown in the Dev Console:

{errors: {}, errorMessages: ["The property relations_contact does not exist."],…}
errorMessages: ["The property relations_contact does not exist."]
0: "The property relations_contact does not exist."
errors: {}
httpStatusCode: {present: true}
present: true

{errorType: 0, infoMessage: "This issue does not exist in any Program or you need additional permissions to access it.", actionType: "[WBS Programs]FETCH_PROGRAMS_FOR_TASK_SUCCESS"}
actionType: "[WBS Programs]FETCH_PROGRAMS_FOR_TASK_SUCCESS"
errorType: 0
infoMessage: "This issue does not exist in any Program or you need additional permissions to access it."
__proto__: Object

Workaround

New Issue View	Old Issue View
Apparently on the New Issue View, on this Field, you can actually set the value to "None" as the option is present.	Add 1 <space> character while on edit mode after clearing the user then save or update the form for it to be cleared.