I had some problems with vertical lines where there were notes that were made cross staves (n, m).
I also had crashes in wanting to move the notes back to the original stave or deleting them (sent to you).
Click on one of the first couple of D notes and press n.
And click on the D in the 3rd beat, then press m,n and you get a spurious line.
I hope this makes sense, otherwise just play around with it a little with doing a few cross staves, chords and lines.
test lines.dorico.zip (532 KB)