Worker: Error: Object captured as exception with keys: reason

[sentry]

Sentry Issue: WORKER-25

Error: Object captured as exception with keys: reason
  File "/app/packages/ws-worker/dist/start.js", line 1377, in Object.callback
    Sentry5.captureException(err);
...
(3 additional frame(s) were not displayed)

[josephjclark]

Absolutely no idea what this is :( There's no information at all in the trace in sentry