Yeah now I see it. Tbh I did not read the message and did not notice the tooltip. I just assumed it said something along the lines "You will lose everything in exchange for gold..." :) Maybe coloring some key words in the message/tooltip, or simply adding colored "n kills/min" to the message would make it more clear. Another option is adding an entry to the right panel showing the total kills/m from the sold pits. It is also very possible most players just read the prestige message and its just me. Also with the pits ticking away in the background selling the pits makes much more sense.
As for the bug, I just had the game running in a background tab in a browser and when I came back to the tab I found it like that. But since you said you never heard from others about this, maybe I would not worry about it for now.
