"From downtown" Steam achievement unlocked upon logging in

Yesterday when I started the game I noticed that the game was extremely lagging. Turned out that Windows was updating, so I super-quitted and wait until it was finished. When I logged back in, the "From downtown" achievement was unlocked. I was near the hedge and the only basketball hoop I built was by the pond near the Frankenline. I attempted throwing rocks and pollens at it like 40 game-days ago, but never succeeded.

Not that I'm unhappy about it, nor was I planning to grind for the achievement, but it's clearly a bug. Unless some bee flying by just threw a pollen inside for me.