Deleted term shown in exposed filter
I think it may be revisions or taxonomy revisions issue 
module documentation  says 
This module enables revisions for the taxonomy terms.

The users will have an option to create new revision for a taxonomy term as for
nodes. This means when a taxonomy term is edited in the default form, a new
checkbox is displayed for revision creation. If clicked a textarea will appear
to fill a revision log message.

Also on the taxonomy term edit page a new menu tab appears after the module
installation which will list all of the taxonomy term's revisions and provides