I have to report an error in zone America/Kentucky/Louisville
zdump gives

      
zdump -V -c 1945,1950 America/Kentucky/Louisville


America/Kentucky/Louisville  Tue Aug 14 22:59:59 1945 UT
        = Tue Aug 14 17:59:59 1945 CWT isdst=1 gmtoff=-18000


America/Kentucky/Louisville  Tue Aug 14 23:00:00 1945 UT
        = Tue Aug 14 18:00:00 1945 CPT isdst=1 gmtoff=-18000


America/Kentucky/Louisville  Sun Sep 30 06:59:59 1945 UT
        = Sun Sep 30 01:59:59 1945 CPT isdst=1 gmtoff=-18000


America/Kentucky/Louisville  Sun Sep 30 07:00:00 1945 UT
        = Sun Sep 30 01:00:00 1945 CST isdst=0 gmtoff=-21600


America/Kentucky/Louisville  Tue Jan  1 05:59:59 1946 UT
        = Mon Dec 31 23:59:59 1945 CST isdst=0 gmtoff=-21600


America/Kentucky/Louisville  Tue Jan  1 06:00:00 1946 UT
        = Tue Jan  1 01:00:00 1946 CDT isdst=1 gmtoff=-18000


America/Kentucky/Louisville  Sun Jun  2 06:59:59 1946 UT
        = Sun Jun  2 01:59:59 1946 CDT isdst=1 gmtoff=-18000


America/Kentucky/Louisville  Sun Jun  2 07:00:00 1946 UT
        = Sun Jun  2 01:00:00 1946 CST isdst=0 gmtoff=-21600


America/Kentucky/Louisville  Sun Apr 27 07:59:59 1947 UT
        = Sun Apr 27 01:59:59 1947 CST isdst=0 gmtoff=-21600


America/Kentucky/Louisville  Sun Apr 27 08:00:00 1947 UT
        = Sun Apr 27 03:00:00 1947 CDT isdst=1 gmtoff=-18000
with a strange transition CST to CDT on 1 January 1946.

        I have searched Louisville newspaper archives and find no report
        of such a clock change around New Year 1946.
I find however the begin of CDT for 28 April 1946, and the
        switch back to CST on 2 June 1946.
Shanks also has the transition on 28 April 1946.
The cause I thnk is the strange formulation of Louisville
        rules
# This also includes Clark, Floyd, and Harrison counties in
        Indiana.

        # Rule  NAME    FROM    TO      TYPE    IN      ON      AT     
        SAVE    LETTER

        Rule Louisville 1921    only    -       May     1       2:00   
        1:00    D

        Rule Louisville 1921    only    -       Sep     1       2:00   
        0       S

        Rule Louisville 1941    1961    -       Apr     lastSun 2:00   
        1:00    D

        Rule Louisville 1941    only    -       Sep     lastSun 2:00   
        0       S

        Rule Louisville 1946    only    -       Jun     2       2:00   
        0       S

        Rule Louisville 1950    1955    -       Sep     lastSun 2:00   
        0       S

        Rule Louisville 1956    1960    -       Oct     lastSun 2:00   
        0       S

        # Zone  NAME            STDOFF  RULES   FORMAT  [UNTIL]

        Zone America/Kentucky/Louisville -5:43:02 -     LMT     1883 Nov
        18 12:16:58

                                -6:00   US      C%sT    1921

                                -6:00 Louisville C%sT   1942

                                -6:00   US      C%sT    1946

                                -6:00 Louisville C%sT   1961 Jul 23 
        2:00

                                -5:00   -       EST     1968

                                -5:00   US      E%sT    1974 Jan  6 
        2:00

                                -6:00   1:00    CDT     1974 Oct 27 
        2:00

                                -5:00   US      E%sT