Stemlets mess up beams which start or end on a rest

[Marcus Macauley]

As the following example demonstrates, beams which begin or end on a rest  
are normally drawn beautifully (with respect to angle and positioning),  
but when stemlets are enabled, these beam angles/positioning are messed up:

\version "2.9.23"
\relative c' {
        c8[ r] e[ r] r[ g] r[ c]
        \override Stem #'stemlet-length = #0.5
        c,8[ r] e[ r] r[ g] r[ c]
        \revert Stem #'stemlet-length \break
	\times 2/3 {c,8[ r r]} \times 2/3 {e[ r r]} \times 2/3 {r[ r g]} \times  
2/3 {r[ r c]}
        \override Stem #'stemlet-length = #0.5
	\times 2/3 {c,8[ r r]} \times 2/3 {e[ r r]} \times 2/3 {r[ r g]} \times  
2/3 {r[ r c]}
        \revert Stem #'stemlet-length \break
	\times 2/3 {c,8[ d r]} \times 2/3 {e[ f r]} \times 2/3 {r[ g b]} \times  
2/3 {r[ c g']}
        \override Stem #'stemlet-length = #0.5
	\times 2/3 {c,,8[ d r]} \times 2/3 {e[ f r]} \times 2/3 {r[ g b]} \times  
2/3 {r[ c g']}
}
\layout { ragged-right = ##t indent = #0 }

In every one of the stemlet beams except the penultimate one, beams that  
should be drawn flat are slanted, and beams that should be slanted are  
drawn flat. The angles and positioning of the beams without stemlets  
should be emulated by the beams with stemlets.

Marcus