I recently had to do a clean install of Big Sur on my iMacPro. Since then, I don't see any notifications from KM, whether from a Notification action or "macro failed". The Notifications panel of System Preferences is set as shown, to allow KM to post.
Thanks for the suggestion. I’ve tried logging out and restarting, so I don’t think that’s the issue. It’s been persistent since the clean install of Big Sur.
I hadn’t, but you have helped me to solve the problem. I went back to the Notifications panel and realised that while KM had all notifications allowed, KM Engine didn’t (I keep forgetting they’re separate applications). Enabling notifications for KM Engine has, of course, done the trick. Whoops.