Investigate random test failure

[gmaclennan]

Commit bf52641 resulted in an unexpected test failure on macos. We haven't seen this before, and it could point to a rare race-condition. It would be worth analyzing the logs for this test run and seeing if we can identify what could cause this error and see if there is a fix and/or a way of reproducing it.

[EvanHahn]

I probably won't take a look soon, but it's now on my list.