As far as I can tell there are a lot of charges of not prosecuting banks from cases that have floated across Frances Grunder's desk specifically (there are accusations the office declined to investigate WF too, and the unverified emails involved were to Frances Grunder as well). In the interest of being as fair as possible (and playing a bit of devil's advocate) the first Intercept article is 100% accurate and fair - the AG office declined to prosecute with no public explanation why, this leaked memo shows that it was heavily recommended to go after OneWest for a seemingly slam-dunk case (signing documents for foreclosure before they were an operational bank). This one is a bit sensational, placing the blame entirely on Harris when it really was a inner office dispute. I say this despite subscribing to the quarterback theory of blame assignment, and she really should be open with what happened even if it takes her some time to put together something accurate. Her voting record will be clear pretty damn quickly under Trump's agenda, I hope this can keep her congressional office cleaner.
As for Mnuchin's defense, I can't find anything to back up his spokesperson's defense that they were compliant with OCC or that OCC has anything to do with fraudulent foreclosure investigations. I think his silence on the memo, and the ad hoc ad hom dismissal of the memo from his spokesperson is what needs a lot of pressure on it now. You can't undo the election that Harris won, but you sure as shit can try and stop Mnuchin now.