initial repeats with non-standard bar style

[Steve Tarr]

Why doesn't the initial bar display in the second case?
-Steve

\version "2.13.31"

% snippet from "Printing A Repeat Sign at the Beginning of a Piece"
\include "firstRepeatOverride.ly"

\score {
    \new Staff {
        \firstRepeatOverride
        \repeat volta 2 {
            \bar "|:" f'1
        }
    }
}

\score {
    \new Staff {
        \firstRepeatOverride
        \repeat volta 2 {
            \bar ":" f'1
        }
    }
}