I am in same situation , MY SP extension from 24 Sept 2019 still in processing , graduated from college on 27 jan 2020 ,Applied for PGWP on implied status 05 FEB, 2020 . Then started working 20 hrs / week . I stopped working 20 hrs once I received official confirmation of study completion from college.After applying for PGWP on implied status , I wrote a letter to CPC edmonton, ( as told by IRCC agent)to explain them about this situation.They received that letter but no reply and no improvement in SP extension processing.