I created a BOM with Mass as one of my columns. I added a row and placed a SUM() at the bottom, which provided the correct sum. Confirmed by exporting to Excel and adding it up there as well.
If I then update various parts (changing the masses of a few parts) the various masses update in the BOM, but the SUM does not update. I deleted the contents of the SUM cell (selected cell and hit delete) and then re-entered the SUM formula, only to be given the same wrong value. It's as if the cell is fixated on the wrong number.
If I add a fresh column for mass, and put a SUM() at the bottom, I get the new correct answer.
So, I have two columns with precisely the same values in them, side by side, adding up to two different sums according to SW.
I obviously cannot trust the SUM() function in any engineering calculations.
If anyone else has seen this weird behavior, perhaps they can state so and SW can look into it.