postgres: using ANY on array of timestamps

Question

I have a Postgres function where I need to check whether or not a particular value is in an array of timestamps. Here's the function:

CREATE OR REPLACE FUNCTION public.get_appointments(
     for_business_id INTEGER,
     range_start DATE,
     range_end   DATE,
     for_staff_id INTEGER
    )
       RETURNS SETOF appointment
       LANGUAGE plpgsql STABLE
       AS $function$
     DECLARE
        appointment appointment;
        recurrence  TIMESTAMP;
        appointment_length INTERVAL;
        parent_id UUID;
     BEGIN
        FOR appointment IN
            SELECT *
              FROM appointment
             WHERE business_id = for_business_id
               AND (
                       recurrence_pattern IS NOT NULL
                   OR  (
                          recurrence_pattern IS NULL
                      AND starts_at BETWEEN range_start AND range_end
                   )
               )
         LOOP
            IF appointment.recurrence_pattern IS NULL THEN
              RETURN NEXT appointment;
              CONTINUE;
            END IF;

            appointment_length := appointment.ends_at - appointment.starts_at;
            parent_id := appointment.id;

            FOR recurrence IN
                SELECT *
                  FROM generate_recurrences(
                           appointment.recurrence_pattern,
                           appointment.starts_at,
                           range_start,
                           range_end
                  )
            LOOP
                EXIT WHEN recurrence::date > range_end;
                -- THIS IS THE LINE IN QUESTION
                CONTINUE WHEN recurrence::date < range_start OR recurrence = ANY(appointment.recurrence_exceptions);
                appointment.id := uuid_generate_v5(uuid_nil(), parent_id::varchar || recurrence::varchar);
                appointment.parent_id := parent_id;
                appointment.starts_at := recurrence;
                appointment.ends_at := recurrence + appointment_length;
                appointment.recurrence_pattern := appointment.recurrence_pattern;
                appointment.recurrence_exceptions := NULL;
                appointment.is_recurrence := true;
                RETURN NEXT appointment;
            END LOOP;
        END LOOP;
        RETURN;
     END;
    $function$;

You'll see that just after the second LOOP statement, there's a CONTINUE statement. I want to skip that iteration of the loop if the recurrence (this is a timestamp, but in text format) variable is either out of range OR if it's listed as part of the appointment's recurrence_exceptions array. The recurrence_exceptions array contains timestamps.

The idea is that if the appointment is listed as an exception, it is not returned. Unfortunately, no matter what I do, it seems that the ANY operator isn't working as expected. To test this, I took one of the values from the recurrence_exception array and changed the CONTINUE statement to:

CONTINUE WHEN recurrence::date < range_start OR recurrence = '2016-09-20 18:07:26';

This did not return that recurrence as expected.

Am I using this properly?

Thank you!