Problems with horizontal brackets

[Jon Arnold]

Hi-
I'm using horizontal brackets to analyze a piece that makes heavy use of
the completion engravers, and I've discovered that the brackets do not
extend the full length of a note when tied over a bar. The bracket only
goes as far as the beginning of the expanded value.

Perhaps the last bit should be filed separately, but the brackets do not
appear at all when using full measure rests.

Here's my example:

%horizontal brackets do not extend the full length of the note
%if used on a note expanded by completion engravers

%they also do not appear at all on full measure rests

\version "2.21.1"

\score {
  \new Staff {
    a1-\startGroup c'\breve-\stopGroup  \break
    r1-\startGroup r\breve-\stopGroup \break
    R1-\startGroup R\breve-\stopGroup
  }
  \layout {
    \context {
      \Voice
      \remove "Note_heads_engraver"
      \consists "Completion_heads_engraver"
      \remove "Rest_engraver"
      \consists "Completion_rest_engraver"
      \consists "Horizontal_bracket_engraver"
    }
  }
}