OSCAR crashes when setting time for oximeter import

[larch]

When I try to import from my CMS-50+ to OSCAR, the program crashes after the import is completed, when I set the start time and then click Save and Finish. This was working fine for me a few times, then it started crashing sometimes and now it seems to always crash. OSCAR 1.2.0 on macOS 10.14.6.

I've pasted the first bit of the OS crash report below and attached the full file. Rebooting doesn't seem to help.

Process:               OSCAR [1605]
Path:                  /Applications/OSCAR.app/Contents/MacOS/OSCAR
Identifier:            org.oscar-team.OSCAR
Version:               1.2.0 (0)
Code Type:             X86-64 (Native)
Parent Process:        ??? [1]
Responsible:           OSCAR [1605]
User ID:               502

Date/Time:             2021-08-28 09:56:07.405 -0600
OS Version:            Mac OS X 10.14.6 (18G103)
Report Version:        12
Anonymous UUID:        51784747-E960-2878-BF1B-3C55A156D650


Time Awake Since Boot: 600 seconds

System Integrity Protection: enabled

Crashed Thread:        0  Dispatch queue: com.apple.main-thread

Exception Type:        EXC_BAD_ACCESS (SIGSEGV)
Exception Codes:       KERN_INVALID_ADDRESS at 0x0000000000000020
Exception Note:        EXC_CORPSE_NOTIFY

Termination Signal:    Segmentation fault: 11
Termination Reason:    Namespace SIGNAL, Code 0xb
Terminating Process:   exc handler [1605]

VM Regions Near 0x20:
--> 
    __TEXT                 00000001010b1000-00000001016bd000 [ 6192K] r-x/r-x SM=COW  /Applications/OSCAR.app/Contents/MacOS/OSCAR

Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
0   org.oscar-team.OSCAR          0x00000001013ba48b SerialPortConnection::write(char const*, long long) + 27
1   org.oscar-team.OSCAR          0x00000001013fa348 CMS50F37Loader:endCommand(unsigned char) + 328
2   org.oscar-team.OSCAR          0x00000001013fa491 CMS50F37Loader::getVendor() + 49
3   org.oscar-team.OSCAR          0x00000001013af5cd OximeterImport::on_saveButton_clicked() + 2957
4   org.oscar-team.OSCAR          0x0000000101436c9e OximeterImport::qt_metacall(QMetaObject::Call, int, void**) + 62