Deleting User from AD breaks searches in JIRA, but doesn't break the existing filters with the same search

When removing a user from AD (user1 in the example), it is no longer possible to perform some seaches in JIRA, like the following:

reporter = user1

However, if there is a saved filter with this search, running the filter will not return any error.

Workaround: instead of remove a user in LDAP, deactive the user. This will not break the searches in JIRA.