"Repeat" commandblocks activate in 1 activaction delay

What i expected to see was that repeat commandblock would act a bit like normal commandblock if it was setting blockdata

{auto:0b}

to itself but when i've put /blockdata x y z

{auto:1b}

to another one, every other output was "The data tag did not change:..."
NOTE!
This bug apparently exist only when activaction blockdata command is placed in chain commandblocks