Halftime plugin crashes Musescore

Install this plugin:

https://musescore.org/en/project/halftimev20

and try to run it on any score. Musescore crashes. I've seen this on Windows 7 and Linux, and in 2.0.3 and 2.1.0. (I also tried the "2017-05-27-2316-master-3d96778" nightly build, but that one crashed when trying to open the "Plugin Manager" window, which is probably a different bug.)

Some info from gdb, in the 2.0.3 Linux build:

Thread 1 "musescore" received signal SIGSEGV, Segmentation fault.
0x0000000000b88e38 in Ms::Chord::upNote() const ()
(gdb) bt
#0 0x0000000000b88e38 in Ms::Chord::upNote() const ()
#1 0x0000000000bc38ed in Ms::Score::addPitch(Ms::NoteVal&, bool) ()
#2 0x0000000000d384ee in Ms::Cursor::addNote(int) ()
#3 0x0000000000d5c4eb in ()
#4 0x0000000000d60318 in Ms::Cursor::qt_metacall(QMetaObject::Call, int, void**) ()
#5 0x00007ffff4cff009 in () at /usr/lib/libQt5Qml.so.5
#6 0x00007ffff4c85cf1 in () at /usr/lib/libQt5Qml.so.5
#7 0x00007ffff4c86a76 in () at /usr/lib/libQt5Qml.so.5
#8 0x00007ffff4c87d42 in QV4::QObjectMethod::callInternal(QV4::CallData*, QV4::Scope&) const () at /usr/lib/libQt5Qml.so.5
#9 0x00007ffff4c9cb3e in QV4::Runtime::method_callProperty(QV4::ExecutionEngine*, int, QV4::CallData*) () at /usr/lib/libQt5Qml.so.5
#10 0x00007fffe0005ead in ()
#11 0x0000000000000000 in ()
(gdb) i r
rax 0x0 0
rbx 0x3e396a0 65246880
rcx 0xffffffff00000856 -4294965162
rdx 0x8 8
rsi 0x0 0
rdi 0x3e396a0 65246880
rbp 0x0 0x0
rsp 0x7fffffff9f70 0x7fffffff9f70
r8 0x7ffff04a7730 140737224800048
r9 0x7ffff7f24800 140737353238528
r10 0x0 0
r11 0x0 0
r12 0x7fffffffa040 140737488330816
r13 0x0 0
r14 0x3de7ea8 64913064
r15 0x0 0
rip 0xb88e38 0xb88e38
eflags 0x10202 [ IF RF ]
cs 0x33 51
ss 0x2b 43
ds 0x0 0
es 0x0 0
fs 0x0 0
gs 0x0 0

(The instructions say that crashes are "critical", so, setting to "critical".)