Steam achievements implementation for UE4 developers: tips and tricks.

When I test in the viewport to make sure my achievements are working, I can trigger them, but only once per editor session. What’s that about? How can I reset them so they trigger every time (so I can repeatedly ensure they’re still working)?

Edit: Also, after packaging–is there any way to see the Steam overlay or test achievements? I try my packaged build and can’t access Steam through it. Is overlay/achievement testing available exclusively in the editor and, eventually, once the game is properly uploaded to Steam?