MacOS Mail delete function has a repeatable bug regarding deleting more than 1 message.
This affects Mail for Catalina and Big Sur. It affects both the delete keyboard key and the delete button with the mouse. It happens about once every 40 messages or so. It is not a stuck key, I have extensively tested the delete key in various apps and it never fails. It does not have anything to do with threaded conversations.
What happens is, say you have 10 messages in your inbox. You have a message highlighted and press the delete keyboard key or use the mouse to press the delete icon. Most of the time, a single message will be deleted, but every 40 messages or so, it will delete the message you're on and the next message down.
I am not pressing the key too long. It never happens in any other app, just MacOS Mail. It happens even with the mouse click on the delete icon. I think it is a timing/scan issue or something - a software bug. Not hardware.
Thanks for looking into this.
MacBook