Musescore reports crash on normal termination (always)

I have just built Musescore 2.1 without problems, as soon as I installed the lame mp3 encoder (congratulations). Unfortunately there is a bug, which was in the 2.0 release, and which is still there. Terminating Musescore, either by closing it's window or by clicking File->Quit causes Musescore to report a segment violation and crash. Apart from the error report the termination appears to be normal. Here are a couple of runs: first terminated by closing the main window, second by clicking File->Quit:
$ mscore
Segmentation fault (core dumped)
$ mscore
Segmentation fault (core dumped)

I tried running Musescore 2.0 under gdb to see if there was anything obviously wrong, but there wasn't. Any suggestions on what to look for would be welcome.

System is 4 processor True Intel running KDE-5.9.8 under Fedora-25 Linux.