Hi @djgoncalves. The names that appear in the assignee drop down list are automatically added based on recency and people who are associated with the task or project. If there is someone remaining in your org, but you don’t assign tasks to them anymore, they’ll drop off eventually. Alternatively, if you completely remove them from the org they will no longer appear on the list.
Note that if a deprovisioned member still shows up in the typeahead when a current Member is assigning tasks, you’ll need to invite them back to a Team for the sole purpose of deprovisioning them.
It’s possible that you removed someone from a Team (in a free Organization), but did not remove them from the Organization. If this is the case, the user will continue to show up in the typeahead. Hope this helps!