volta repeat's alternative vs. tie

[CSÉCSYLászló]

Dear Lilypond people,

the first note of the second \alternative (which is a tie-end, as the last note
of the \repeat has a tie after it) doesn't get it's tie (at least in 2.8.4) as
it should:

%<----
\repeat volta 2 { g1~ } \alternative { { g | a } { g | r } } f1
%<----

Think this way: if I have lyrics attached to the score, the \repeat's last
syllable should last for the second \alternative too, not just the first one.
Now I have to place an extra underscore before the last part (here: the part
after the \repeat-\alternative's end bar), which is quite annoying, and (I
think) unobvious. Is this by design, a bug, or have I missed something?

Bye
Boobaa