Hello,
While the basic output of barlines in grouped staves has improved in 2.17.14, there is still a problem if there is a dynamics staff included. The following code produces the expected output in 2.16.1 but is broken in 2.17.14:
\score {
\new PianoStaff <<
\new Staff { c'1 }
\new Dynamics { s1\p }
\new Staff { c'1 }
>>
}
\score {
\new StaffGroup <<
\new Staff { c'1 }
\new Dynamics { s1\p }
\new Staff { c'1 }
>>
}