bug - wrong ties at octavation

[Matthias Kupfer]

Hello,

at least in version 2.8.5 of lilypond I found following bug: ties for notes with
same pitch are not correct as long as one note (of chord) is octavated. Ties are
made, but not for the correct note. (see example code) It seems to me like:
pitch is considered but neither octavation nor note head position.

Example:

{
 <c c'>~<c' c''>
#(set-octavation -1)
 <c c'>~
#(set-octavation 0)
 <c' c''>
#(set-octavation -1)
 c'~
#(set-octavation 0)
 c'
}

Matthias