Q: Pending h4 petition and i94 expired, is it unlawful stay

My employer filed h1b extension on sept 2017. My i94 expired in October 2017. I filed a petition I539 (transfer from h1b to H4) on 07/11/2018 while my h1b extension was pending and my I94 was already expired. I got the H4 receipt on July 16, 2018 based on my spouse valid h1b and my h1b extension got denied on July 24, 2018. I have been staying here based on H4 receipt. My question is Do I am on authorized stay?Someone told me that I am acquiring unlawful presence from the date my h1b denied.

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