Has anyone had an I-539 Change of Status to F-1 approved after deferring their program start date?

I’m currently in J-1 status and filed an I-539 Change of Status to F-1 (Master’s program) before my current status expires. I recently upgraded my case to premium processing.

My J-1 status is valid until November 16, 2026. On my I-539, I requested an effective change of status date of August 17, 2026, which is well before my J-1 expiration date. My original program start date is August 20, but if USCIS doesn’t make a decision before classes begin, my university is willing to defer my admission to January and issue me a new I-20. I would immediately send the updated I-20 to USCIS before they make a decision.

I also have a domestic flight scheduled for August 16, one day before my requested effective change of status date. Because of everything happening with immigration enforcement recently, I’m feeling very anxious and worried about whether I’ll be okay to travel while my I-539 is still pending.

My main question is:
If USCIS approves my I-539 in September after receiving my updated I-20 with a January start date, would I remain in valid F-1 status between the approval date and the January program start date?

And as a secondary question:
Would you feel comfortable taking a domestic flight on August 16 while still in valid J-1 status and with a pending I-539, or would you avoid traveling?

Has anyone been in a similar situation or had their COS approved after deferring to the next semester? I’d really appreciate hearing about your experience.