I took some time off between July 22, 2017 and Dec 11, 2017 from quantopian. In between that time something changed in the system to where a algorithm I was backtesting which used to get 1642.37% now gets 677.19%. I am not quite ready to post my algorithm but here are the things I checked:
1) Code is the same. (I like the new back test compare buy the way).
2) Date range for back test is the same. Jan 03 2003 - Jul 21 2017
3) I have been trying to find a post that would suggest data or api changes that I need to make. Only I thing I found was faster Fundamental API for accessing morningstar data. I changed to Fundamental API and still get 677.19% returns.
Without being able to add more logging to the algorithm and run on the data back in July 2017, I am at a loss. So I am looking for anything people know has changed I should focus on. Thank you in advance.