Assertion Failure: UI Testing Failure - Failed to receive completion for XCDeviceEvent: page 12 usage 64 duration 0.01s within 10.0s

My UI tests randomly fail with

Assertion Failure: UI Testing Failure - Failed to receive completion for <XCDeviceEvent:0x7f9783e15220 page 12 usage 64 duration 0.01s within 10.0s

I am using Swift 2.1 and Xcode 7.2 (7C68).

Killing the simulator and rerunning the tests usually fixes the issue, what could be wrong?