To reproduce, Go to tutorial/etsy-spring
For either 'stable' profile or the main one, change core to 3.5-beta-3
Run that, note the existence of "WebDriver has not been found for this thread" exception in the log, and shortened run.
For either 'stable' profile or the main one, change core to 3.5-beta-2 (the release before)
Run that, note the exception in (2) is not seen.
Thus the bug/regression was introduced between the the 3.5-beta-2 and 3.5-beta-3 releases of core.
Note you will have to comment out some of LifecycleSteps.java to do this experiment.