In the test harness, it sometimes will not use the latest saved code. It's inconsistent. But, this latest stretch has gone on for 10 minutes.
I've just made a change, fired up the test harness and using the debugger, I can see my change.
Are you using the debugger?
Same problem here. You have to do it pretty fast( <10 seconds for me). I've had it happen where the debugger is showing new code but old code is being run.
This happens because we have to publish the game to the preview service every time you save your game, and this takes a few seconds.