arpeggio rendered wrong when exported as PDF

This applies to MuseScore 2.0 beta 2 a925ae0

I place an arpeggio on a chord, and it displays beautifully within MuseScore. Then I export the score to a PDF file. I look at the PDF file, and now the arpeggio symbol has gone out of control. It is no longer a discernible arpeggio symbol at all: each squiggle is vertically separated from all the others by a large amount of space, and the whole of the now-distended symbol extends up beyond the height of the staff. In cases where I have lengthened the symbol to cover more notes of the arpeggio within MuseScore (which displays perfectly), the PDF-exported symbol can extend beyond the top of the staff even off the top of the printed page.