tsvector_update_trigger() fails in 9.6 on character(2) column

I am migrating a 9.3 database to 9.6, and came across what looks like a possible regression somewhere in tsvector_update_trigger() when passed a column of type character. The following works in 9.3:

CREATE TABLE public.foo (
foo_id integer NOT NULL,
country character(2) NOT NULL,
fts tsvector,
CONSTRAINT foo_pk PRIMARY KEY (foo_id)
);
CREATE TRIGGER maintain_fts
BEFORE INSERT OR UPDATE
ON public.foo
FOR EACH ROW
EXECUTE PROCEDURE tsvector_update_trigger('fts', 'pg_catalog.english', 'country');

INSERT INTO public.foo (foo_id, country) VALUES (1, 'US');

But the same thing in 9.6 results in :

ERROR: column "country" is not of a character type

I traced this back to tsvector_update_trigger() because if I disable that trigger the INSERT statement will succeed.

If I change the column to character varying(2), then the INSERT succeeds as well.

Kind regards,
Matt