I found a bug in Chrome 87.0.4280.67. It is not present in Canary 89.0.4334.0. An unwanted grey border or box appears on or near a <fieldset> element when there is a combination of border-radius, background, and a border color with an alpha transparency. The issue was reported to the Chromium team a few days before.
This week I finished reading The Big Sleep by Raymond Chandler and started Farewell My Lovely. I’ve noticed several references to Iowa in these two reads, he seems to have spent some time in the state.