iPad Pro M1

I purchased the M1 iPad Pro about six months ago and right after it arrived, I charged it using the USB charger of 30 watts that came with my new M1 MacBook Air, as I had read that it was okay to do that. Shortly after I charged it with the MacBook Air charger, there was a vertical line that ran across the screen. Because I was well within the 14 day exchange/refund window Apple replaced the iPad for me, but since then I have been afraid to use the 30 watt charger again, even though I read everywhere that it's okay to use it. Thoughts? Was what happened to me just a coincidence, or could it have been the charger that ruined the iPad?