Unassigned Issues do not Show up in Issue Search Results when Assigned To Field is Grouped

Why do unassigned issues disappear when Assigned to field is grouped and what should be done to have them show up in the results?

 Below are the steps to take to check the reason why the unassigned issues disappears from search results when Assigned to field is grouped:

1. Try to ungroup the Assigned to field of an issue search and notice in the results that the unassigned issues have the value of " < Unassigned > " whereas, with a case search, the unassigned cases have NULL value or blank. This in effect, shows the unassigned cases as –None- for Assigned to field when it is grouped and with issues, the unassigned issues are removed from the results.
2. There are certain symbols that the NetSuite recognizes to be another element like "{ }" for example, the system recognizes it as a tag and probably html code for "< >" found in the Unassigned value of the issue.
3. Even formula does not resolve the issue, because the formula does not also capture the " < Unassigned > " value therefore, could not strip the < > signs.
4. Work around is to update all unassigned issues first and have them assigned to a dummy employee (i.e. name the employee 'Unassigned') then group the Assigned to field.