Currently, the custom radio field has the following specifications.
—
https://jira.atlassian.com/browse/JRACLOUD-75541
1. When we have a custom radio select field marked as not required it displays  `none` option in issue view/edit and issue transition screens but will not in issue create screen.
2. When we mark a custom radio select field as required it will not display `none` option in all issue view/edit, transition screen and issue create screen.
—

When we have a custom radio select field marked as not required, it will not be in the issue create screen.
Therefore, once we select an option on the creation screen, we can't return it to the unselected (none) state.

If a custom radio selection field is marked as not required, please display a "none" option on the issue create screen like the same other screen.