Treble clef in classic guitar should not be octave-transposing
The classic guitar is a transposing instrument since it is written using the treble clef but it sounds an octave lower. However, when choosing classic guitar in MuseScore 2.3.2 the proposed clef is the treble clef with an ottava bassa. This is not the usual way to notate the guitar, which uses a plain treble clef (see modern guitar authors such as Leo Brower or classical ones such as Sor and Giuliani). There is a workaround: select the normal treble clef and in staff properties set transpose written pitch one octave lower. But this should be the deafault setting, not a workaround.