On June 19, I posted this:
"A few days ago, it was time to pay some monthly credit card bills. I have them scheduled so I don't forget about them, but I initiate the payments out of my checking directly at the websites of the cards. I had some scheduled for the 15th and some for the 16th. I paid them all on the 15th. I marked the transactions as paid and did not give it a second thought. I think I quit Quicken for Mac after that. Later, I went back to Quicken for some reason and was surprised to see my bank account show in the red after a July 1 payment. After a brief panic, I found that three of the credit card payments were duplicated. Two of them had been scheduled for the 15th and one for the 16th. Two other payments I had made that day had not been duplicated. I did not think to make a screenshot."
It has happened every month since then. It is not a download matching problem. When I pay my credit card, I mark the scheduled transaction as paid, I adjust the date if necessary, and I also put the word "paid" in the memo field. It is always one or more of the same scheduled transactions. I have taken a Screenshot each month but I attached only the latest.
I am on an iMac running Ventura 13.6.9. Quicken Version 7.9.1 (Build 709.54540.100)