Wide spacing after extremely long syllable

[Mark D. Blackwell]

After an extremely long syllable in the lyrics, the next measure's
spacing is quite wide, even with ragged-right (in version 2.19.37).

The problem does not occur in version 2.18.2.

I attach PNGs for versions 2.18.2 and 2.19.37.

In the tiny example (below), the problem measure (of two eighth notes)
comprises the word, "shine".

I tried the following (before each of those eighth notes), but they
didn't shrink the problem measure:

    \once \override Score.SpacingSpanner.average-spacing-wishes = ##t
    \once \override Score.SpacingSpanner.common-shortest-duration =
#(ly:make-moment 1/8)
    \once \override Score.SpacingSpanner.base-shortest-duration =
#(ly:make-moment 1/8)
    \once \override Score.SpacingSpanner.shortest-duration-space = #0.1
    \once \override Score.SpacingSpanner.spacing-increment = #1.2

Although the following shrinks the problem measure, it places the
second eighth note completely after the word, "shine" (which looks
bad):

   \once \override Score.SpacingSpanner.packed-spacing = ##t

For good results similar to that of version 2.18.2, I wish to shrink
the problem measure (after the extremely long syllable) to a
more-normal spacing, while still aligning the word "shine" under both
its eighth notes (as normal).

I wish to keep the extremely long syllable and the problem measure
together on the same system (also called "line").

I don't mind the placement of the barline before the problem measure;
I plan to hide it, anyway.

The following \notes variable corrects this spacing problem (perhaps
interestingly).

However, with this approach, the whole note must comprise a full
measure (which is impractical for general use):

notes = \relative c'' {
  \override Score.SpacingSpanner.common-shortest-duration =
#(ly:make-moment 1/4)
  \time 65536/1
a1*65536
  \time 1/4
a8[( c]) \break
  \time 1/4
a4
}

Here's the tiny example:

\version "2.18.2"
\paper {
  left-margin = 5\mm
  right-margin = 5\mm
  ragged-right = ##t
}
\layout {
  \context { \Staff
    \remove "Time_signature_engraver"
  }
}
theLyrics = \lyricmode {
  \once \override LyricText.self-alignment-X = #LEFT
Rest_eternal_grant_unto_them,_O_Lord,_and_let_light_perpetual_
shine on
}
notes = \relative c'' {
  \time 1/1
a1
  \time 1/4
a8[( c]) \break
  \time 1/4
a4
}
\score {
  <<
    \new Staff
      \new Voice = "one" \notes
    \new Lyrics \lyricsto "one" \theLyrics
  >>
}

2.19.37-book.png
Description: PNG image

2.18.2-book.png
Description: PNG image