http://www.cic.gc.ca/english/helpcentre/answer.asp?qnum=1181&top=15
As Per above link, it is LEGAL to work after you submit PGWP. However, it doesnt mention about “ Will this working time count for EE work experience”
To be safe, I suggest you should not count this period, but still mention this period on your EE Application and PR application.
I was struggled with this several times because there was no statements fully covered this question in CIC webpages.
For my case, I didn’t count implied status working period; and even I worked extra 1 and a half month before I made an EE profile. This would keep me a nice sleep at night when I wait for my PR application to be approved.
I am still waiting for decision from IRCC office and will keep you update
Good luck, folks