Just sent this to support, posting here as a notification to anyone else.
It appears that within the last couple of days there has been a change. I have several views in Menu or bottom nav-bar prominence, with a show_if condition of FALSE. These views can be navigated to (via action and/or custom nav menus), but the views are now showing up completely blank. Example:
Removing the FALSE appears to fix the issue.
This is a common technique to block views from overriding inline views (by keeping them out of Ref prominence), but keep them from showing up in the menu/nav-bar.
