Change of status from J1 to H1B with 212E Waiver?

[gandalf314]

I am a J1 Post-Doctoral Researcher at a major public research university.
Both my J visa and DS2019 have endorsement from the Visa Officer that I am NOT subject to 212E the 2 year rule. My skills are on my home country's skill list.

Because the decision of Department of State is final in this matter, I formally applied for and was granted a waiver in Jan 2019. (I612 - Application to waive foreign residence requirements)

Meanwhile, an industrial employer had filed a H1B petition on my behalf in Apr 2018 and this petition has been hit with a RFE asking for the waiver document. I have submitted the waiver document to the legal team and I haven't heard back yet.

My question is, because the H1B was filed on Apr-2018 and I got the waiver from 212E only on Jan-2019 can USCIS deny my H1B petition saying the waiver hadn't been granted yet on the date of filing of H1B?

Has anybody in the forum been in a similar situation where the 212E waiver came AFTER a H1B petition was filed?