Solution Plex

A contact was added through the Messages module and a conversation was initiated with that contact. Later, when opening the chat and clicking on the three-dot menu, the option to Tag Contractor was selected.
The contact that was added through the Messages module appeared in the contractor selection list, even though no contractor record had been created for that contact in the Contractor module.
This behavior is incorrect because only users who have been explicitly created and registered as contractors should be available in the contractor tagging a task list. Regular contacts added through messaging should not be treated as contractors.