Just installed a Gigabyte Aorus Ice 5090, and a new Corsair hx1200i psu (2050 50 series version). Night one saw a spark like light at the dreaded gpu cable connection. Thought I was just crazy and imagining it after seeing the horror stories. Night two I recorded my power down using windows shutdown. I ensured this morning all connections were very firm and seated correctly, and saw the same flash tonight.
Took a video but can’t link in this forum so here is the frame of the video you can see it flash.