Volta spanner missing edge when using "|" as endRepeatType

[Andy Bradford]

Hello,

I want to place an interlude that  happens only the first time through a
a section that has  a repeat and a second interlude  for the second time
through. I don't want the repeat measure bar showing up in the middle of
the piece, so  I set the endRepeatType  to "|", but when I  do that, the
right edge of the volta spanner  loses the stright edge line. I've tried
various combinations of bars to see if  I can get it to work but haven't
succeeded so far.

I also tried  just using a solid  line Text spanner but  couldn't find a
way to get any text "inside" the spanner (only on the ends).

Any clues on how this could be done?

%%%%%%%
\version "2.22.2"

voltaprima = \markup { \text \italic { First time only } }
voltaseconda = \markup { \text \italic { On repeat only } }
\relative {
  c''1
  \repeat volta 2 {
  c
  \once \set Score.startRepeatType = "|"
  \set Score.endRepeatType = "|" % or "||"
  \set Score.repeatCommands = #(list (list 'volta voltaprima) 'start-repeat)
  c4 b d e
  \set Score.repeatCommands = #(list (list 'volta #f) (list 'volta voltaseconda)
 'end-repeat)
  c b a b
  \set Score.repeatCommands = #'((volta #f) end-repeat)
  f'1
  \set Score.endRepeatType = ":|."
  e
  }
  \alternative {
    { d }
    { a' }
  }
  f \bar "|."
}
%%%%%%%

Thanks,

Andy