When I go to look for this setting again in my home instance, I find that it is in fact now correctly set. It was not correctly set when I posted. So my fix stuck.
I’m using sync on Android and I don’t believe that I can change the setting there. I can change the setting for whether I filter bot accounts, and so that confused me for a bit about whether I was misinterpreting that setting.
I did find the setting in a web browser on my home instance. And I thought I corrected it, and I thought I saved my change. Updates and screenshots to follow momentarily.