time signature and grace note

[Niels]

I have a score with two voices on a staff.

Is this a bug or am I doing something wrong?

Regards, Niels

\version "2.20.0"
melody = \relative c'' {
  <<
    {\time 4/4 \grace {c8} c4 d4 f2
     \time 2/4 \grace {c8} c4 d4}
    \\
    {\time 4/4 a,4 b c2
     \time 2/4 a4 b}
  >>
}
\score {\melody}

At the beginning of a measure I include a time change as well as a grace note. After compilation the time signature is included twice and the grace note is found between the time signatures (see attachment).

test08.pdf
Description: Adobe PDF document