Welcome! This forum has a treasure trove of great info – Scouters helping Scouters! Just a heads up, though - all content, information, and opinions shared on this forum are those of the author, not the BSA.
There is a bug keeping scouts and parents in events even beyond the grace period. It’s been reported to the developers, but there’s no timeline on when it might get fixed.
What is different here is that you’re reporting it’s happening for new events too. The bugs I’ve seen have been limited to events created while the scouts were still on the roster, so the bug you’ve identified may or may not be related to the already-known bugs.