Double hyphens in lyrics

[Alberto Sala]

Hi everyone!
In the following fragment of music, Lilypond prints a double hyphen on the last
note of the slur.

 \version "2.10.0"
MusicaUno = \relative c'' {
        e8. e16 e4 d8. d16 d8 d
        d4( c) b b
}
Parole = \lyricmode {
        Ky -- ri -- e, Ky -- ri -- e e --
        lei -- son, e
}
\score {
        <<
        \new Voice = musicone { \MusicaUno }
        \new Lyrics \lyricsto musicone \Parole
        >>
\layout { }
}

It's a strange behaviour, in fact it happens with last note of slur being "c"
"f" or "g" but not with "e" "a" or "b".
Thank you for your reply.

Alberto