In a very rare case, the randomisation may cause all users to be on one
team, causing a test failure. The odds make it basically impossible, but
if adjusting the number of users in the test scene this can more readily
be hit.
The import process was running on the async load thread, but then
accessed from the access thread later on. This seemed to somehow pass
fine in headless runs, but would fail on visual test execution
(specifically on `TestBeatmapConfirmed()`).