@TillmannTaape , can you confirm that the script used at the end of the first <ab> (quoted below) is italic? If so, can you add emph tags?
"Manus meÓ• fecerunt organum et digiti mei aptarunt psalterium"
Yes it's italic script. I've added emph tags. The markup was inconsistent re body part and la tags, so I tidied it up.