I first experienced that in Catalina, and although I'm pretty sure it was perpetuated in Big Sur, I'm not 100% certain. It was too minor to aggravate myself over in the larger context of Big Sur. (For what it's worth, I run with SIP disabled.)

I doesn't happen in my inbox either, but it does happen in my trash and maybe my sent box.

It's most annoying!

Update: It happens to me in trash, but only with sequential messages, not when there's an extraneous one stuck in between.


The new Great Equalizer is the SEND button.

In Memory of Harv: Those who can make you believe absurdities can make you commit atrocities. ~Voltaire