Just upgraded to latest version as of today, and I have US units selected under the general settings. I was looking at the "Mapped Area" value under the "Edit" menu at right side of project. The value there looks to be off by roughly a factor of 10. (ie. showing 40,000.00 acres instead of true value of 4,000.00).

The mapped area in square kilometers also looks to be a bit off, although much less than a factor of 10.

Perhaps I'm doing something wrong, but perhaps a bug?

I don't see an issue here, but if you have some concrete examples please do forward them to This email address is being protected from spambots. You need JavaScript enabled to view it. and we can take a look. Note that the "mapped area" field relates to the rectangle used to define the area of map generation - it does not refer to the amount of water in this rectangle. Consequently mapped area might be quite a bit larger than the size of the waterbody being mapped.