Modern Events Issue

Wondering if anyone else is seeing this in their SharePoint Online tenant - on any modern page - either a Group-based Team Site or a new Communication Site - if I click in to an Event page and then click a link to go back home (either the Home link itself or the site icon), I see an error briefly displayed in a light-red band near the top of the page that says "This link is not valid.  Check the link and try again."  It then disappears and the home page loads normally.

I was just about to show someone a new Communication Site for the first time and think that would mar the experience as I've created a few test events (which look great by the way with a banner photo and map) and each time I go back home the error is there.  I tried other browsers and other modern sites and I seem to be getting it with events every time.  My colleagues see it too.  When attempting this with Communication Sites specifically, I see the links under the name at the top of the page take a longer time than usual to appear on Events pages too - this does not happen with say a News page.  I don't see the error with those either.