Height of markup entered on a Dynamics Staff

[Richard Shann]

In the following snippet the text is displaced vertically upwards if
the commenting out is removed, i.e. a note appears with more than one
leger line later on the staff.
8><8><8><8><8><8><8><8><8><8><8><8><8><8><8><8><
\version "2.24"
MI = {
        <> ^\markup \bold \italic {"text" } 
        R1*4/4
        R1*4/4
}
MII = {
         R1*4/4
         R1*4/4
         c''1 
         %c'''1
         
}
\score {
          <<
              \new Dynamics \MI
              \new Staff  \MII
          >>
       }
8><8><8><8><8><8><8><8><8><8><8><8><8><8><8><8><

Is this a bug?

Richard