Around Dec 8th my profit tanked:
I however see no reason for such a big drop... I have no single question with sufficiently large negative profit, and there are very few questions overall where my total investment is above 1K none of which appear to have turned hugely in my disfavor recently...
Was there a change in profit calculation or something else weird happened?
The same happened to me on similar date. My profit also increased (approximately the same amount as was my loss) when there was a bug with missing loan. They run script correcting the loan bug, but it distributed unearned profit cca in the size of the loan. I believe in Dec 8, they run a script that recalculated profit from scratch, thus removing the unearned part.
To be sure, I would have to go cross-checking the exact values and dates. So I am not sure, but this in my best guess. (Maybe someone will confirm).