Unexpected warning message

[Paul Hodges]

The code below produces exactly the output that I expect. (It is extracted from a very complex bit of notation - trust me that things like the way the grace notes are written have a good reason in context.)

My concern is that as well as producing the expected output, it also generates a warning message:

C:/Users/PAUL~1.CAS/AppData/Local/Temp/frescobaldi-hq45qbn3/tmp6a3tkp_s/document.ly:8:12:

warning: Ignoring grob for slur: TrillPitchAccidental.  avoid-slur not set?

  cs8[)\fp

               \startTrillSpan ds

What does this even mean, and is there any way to resolve it?

Paul

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\version "2.24.0"

\language english

\relative e'' {

  \magnifyMusic 0.67 { \stemUp e!8*1/16[\ff^( fs e] }

  \stemDown \pitchedTrill

  cs8[)\fp \startTrillSpan ds

  s4 

  \parenthesize cs8\<

  \hideNotes \set stemRightBeamCount=1 cs8*1/16]\f \stopTrillSpan

}

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