Calculation of treasures seem to be incorrect sometimes

[Viktoriusiii]

I was just digging... and found NOTHING! The whole area of the remaining circle, just nothing...

I started digging around the circle randomly until I saw this.
Yes it is only one block, but this one block was kinda annoying because I triggered like 6 zombiehordes or something
And it had to be outside of at least one more stage (because everything was already cleared at the previous stage)

Not the biggest issue... still something that might want to be looked at (since it might only be a small numerical error)