Big Sur - Chrome/Edge developer tools prevents sleep

I am a software developer and recently upgraded my MacBook Pro to Big Sur and, since that time, have found that it will not sleep. It turns out, by looking at the Energy tab on the Activity Monitor (which has a column telling you which apps are preventing sleep), that the offending app is Google Chrome - but only if I open the Developer Tools AND undock it. If the developer tools are not open (or they are open but docked) then everything works s expected. As soon as I undock it the "Preventing Sleep" column changes to "Yes". I tried MS Edge for Mac - same thing. Firefox - no problem.

Am I all alone in experiencing this annoyance?