I'm getting:

Error 037: Invalid plot value "Obj" SPY at #4096

When training my script with two or more parameters (2+ optimize() calls), I get the above error, then Zorro crashes. It works fine with 1 parameter. I think the error is happening when Zorro is trying to generate the optimization charts. I tried commenting out all plot() calls in my script. It looks like it's generating the .par files fine.