Notice of Default after chapter seven discharge

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I'm wondering if anyone can help me with this question. 

Filed chapter seven last year, included the house (surrendered) and was discharged Nov. 2017.  Am presently living here saving money for next home, and because I'm closely following my credit score, saw a 60 point drop the other day. After researching online the steps bank takes to foreclose, I'm wondering if they've filed a notice of default. Can they do that after my mortgage was discharged? I'm told there is "something in the mail" I have to sign for and have not received it yet. 

Is that a violation of my discharge, to file a notice of default on a loan that no longer is valid? 

All I care about is my credit score, and know this place could go to auction soon. 

Thanks if anyone knows