I have a python function that isn't pure (in gcc terminology), it has inputs that don't come from the sheet itself -- in my case, it looks up a ticker symbol on yahoo (maybe there's a better solution for this? but a python function works mostly fine).

When I start up gnumeric with the spreadsheet, it loads the data and calculates all cells depending on this one, which is fine.

Gnumeric will also re-evaluate the function when I go into that cell and just hit enter to re-enter the same function call into it (the cell contents is "=myfunc(...)").

However, in this case, while gnumeric displays the new value in the cell, other cells depending on this value aren't recalculate. E.g. if the value of this cell, say it's A9, changes from 1 to 2, another cell that has e.g. "=2*A9" (and also its dependents) won't actually change from 2 to 4 until I close the spreadsheet or do something else that forces it to recalculate, like changing the number of displayed digits.