Case statement not pulling time between 18:31:01 and 19:00:00

My data has four columns date, departure, destination and depart time. I have a case statement that groups depart times. It works fine but it does not group departures between 18:31 and 19:00. Time is
Any idea why not? Thank you for your help.
SEL
dept_date,
depart,
dest,
depart_tm ,
CASE
WHEN depart_tm BETWEEN '00:00:01' AND '00:30:00' THEN '0000AM'
WHEN depart_tm BETWEEN '00:31:00' AND '01:00:00' THEN '0030AM'
WHEN depart_tm BETWEEN '01:01:01' AND '01:30:00' THEN '0100AM'
WHEN depart_tm BETWEEN '01:31:00' AND '02:00:00' THEN '0130AM'
WHEN depart_tm BETWEEN '02:01:00'AND '05:00:00' THEN '0200AM'
WHEN depart_tm BETWEEN '05:01:00' AND '05:30:00' THEN '0500AM'
WHEN depart_tm BETWEEN '05:31:00' AND '06:00:00' THEN '0530AM'
WHEN depart_tm BETWEEN '06:01:00' AND '06:30:00' THEN '0600AM'
WHEN depart_tm BETWEEN '06:31:00' AND '07:00:00' THEN '0630AM'
WHEN depart_tm BETWEEN '07:01:00' AND '07:30:00' THEN '0700AM'
WHEN depart_tm BETWEEN '07:31:00' AND '08:00:00' THEN '0730AM'
WHEN depart_tm BETWEEN '08:01:00' AND '08:30:00' THEN '0800AM'
WHEN depart_tm BETWEEN '08:31:00' AND '09:00:00' THEN '0830AM'
WHEN depart_tm BETWEEN '09:01:00' AND '09:30:00' THEN '0900AM'
WHEN depart_tm BETWEEN '09:31:00' AND '10:00:00' THEN '0930AM'
WHEN depart_tm BETWEEN '10:01:00' AND '10:30:00' THEN '1000AM'
WHEN depart_tm BETWEEN '10:31:00' AND '11:00:00' THEN '1030AM'
WHEN depart_tm BETWEEN '11:01:00' AND '11:30:00' THEN '1100AM'
WHEN depart_tm BETWEEN '11:31:00' AND '12:00:00' THEN '1130AM'
WHEN depart_tm BETWEEN '12:01:00' AND '12:30:00' THEN '1200N'
WHEN depart_tm BETWEEN '12:31:00' AND '13:00:00' THEN '1230PM'
WHEN depart_tm BETWEEN '13:01:00' AND '13:30:00' THEN '0100PM'
WHEN depart_tm BETWEEN '13:31:00' AND '14:00:00' THEN '0130PM'
WHEN depart_tm BETWEEN '14:01:00' AND '14:30:00' THEN '0200PM'
WHEN depart_tm BETWEEN '14:31:00' AND '15:00:00' THEN '0230PM'
WHEN depart_tm BETWEEN '15:01:00' AND '15:30:00' THEN '0300PM'
WHEN depart_tm BETWEEN '15:31:00' AND '16:00:00' THEN '0330PM'
WHEN depart_tm BETWEEN '16:01:00' AND '16:30:00' THEN '0400PM'
WHEN depart_tm BETWEEN '16:31:00' AND '17:00:00' THEN '0430PM'
WHEN depart_tm BETWEEN '17:01:00' AND '17:30:00' THEN '0500PM'
WHEN depart_tm BETWEEN '17:31:00' AND '18:00:00' THEN '0530PM'
WHEN depart_tm BETWEEN '18:01:00' AND '18:30:00' THEN '0600PM'
WHEN depart_tm BETWEEN '18:31:00' AND '19:00:00' THEN '0630PM'
WHEN depart_tm BETWEEN '19:01:00' AND '19:30:00' THEN '0700PM'
WHEN depart_tm BETWEEN '19:31:00' AND '20:00:00' THEN '0730PM'
WHEN depart_tm BETWEEN '20:01:00'AND '20:30:00' THEN '0800PM'
WHEN depart_tm BETWEEN '20:31:00' AND '21:00:00' THEN '0830PM'
WHEN depart_tm BETWEEN '21:01:00'AND '21:30:00' THEN '0900PM'
WHEN depart_tm BETWEEN '21:31:00' AND '22:00:00' THEN '0930PM'
WHEN depart_tm BETWEEN '22:01:00'AND '22:30:00' THEN '1000PM'
WHEN depart_tm BETWEEN '22:31:00' AND '23:00:00' THEN '1030PM'
WHEN depart_tm BETWEEN '23:01:00'AND '23:30:00' THEN '1100PM'
WHEN depart_tm BETWEEN '23:31:00' AND '23:59:00 'THEN '1130PM'
END AS timeinterval
FROM
Finallift
EG. output

Depart

Dest

Depart_tm

timeinterval

MSP

KEF