Here's my experience. I had no idea what I was thinking. Way back I bought the wrong viscosity 5w30 by accident. Changed my oil and went about my days. I didn't realize it till I was about to do the NEXT oil change, because I had the old jugs of used oil in the garage. I should have just listened to my instincts and changed back to 5w20 right then. I told the story to a few friends and family and they convinced me with their powers of persuasion (bro-science) to keep it 5w30. Long story short, I've been riding this thing for years now with that viscosity and no problems or codes whatsoever. I'm right around 75k miles and she still rumbles like a champ!
My bros seemed to think that if I would have changed it back, the thinner viscosity could have caused a leak. Is there any truth to that? I'm asking because I still contemplate on changing back to 5w20 even after all these years.
Either way, silly move on my part. I was also changing my wife old Accord's oil which is why there's a Fram filter on that receipt. I use to put 5w30 in that car and that's probably where I mixed things up.