Ryan, a Google engineer, stated that incorrect Schema is a problem from spam’s perspective and a synchronization perspective.
Google often sees Schema that is inconsistent with core content.
The effect may be the same: A negative message, which makes your content less compatible with the search query or the user intent and not more.
Ryan’s podcast point raised different ideas.
Maybe a website advertises a monthly meetup?
The author may add Event Schema markup in the first month with dates and times. However, the dates are updated on the human side of content, but they now have an incorrect schema.
Or worse, more event Schema is added to Google and tells Google that the event has multiple dates. This might be true, but it won’t help users trying to find the next one.
This could become a problem when SEO professionals try to grasp Schema quickly without spending the time to understand it fully.