Unable to shutdown mono/Sonarr

Sonarr version (exact version): 2.0.0.5344
Mono version (if Sonarr is not running on Windows): 6.8.0.123
OS: MacOS Catalina 10.15.4
Debug logs: https://filebin.net/8bpv5hcwgss518tm/sonarr.trace.txt?t=jt5te4i5
Description of issue: When I shutdown Sonarr from the GUI, the mono process doesn’t actually quit. When I restart Sonarr, it works, but now adds a second mono process. This continues indefinitely until I go through and manually kill the mono processes. The grep below shows the multiple processes after quitting and restarting Sonarr. Weirdly, if I quit Sonarr immediately after starting it, the mono process quits correctly. But if I wait 30s or so, and then try to quit it, it hangs as described.

USER    52548 118.6  1.2  4517772 156052 s008  R+    8:45am   1:19.46 mono --debug /Users/USER/Applications/Sonarr.app/Contents/MacOS/NzbDrone.exe
USER    52564 116.1  1.3  4513684 159160 s001  R+    8:46am   0:40.03 mono --debug /Users/USER/Applications/Sonarr.app/Contents/MacOS/NzbDrone.exe
USER    52581   0.0  0.0  4268284    676 s000  R+    8:47am   0:00.00 grep Sonarr