Might be a question for support, @sudsy, as it’s surprising and new-to-me, too.
(Of course, it totally makes sense for Bubble to require one to use ones own keys here, this message is a lot more aggro than the older ones – and for those of us who make a lot of demo apps, it’s kinda shitty to aggressively require keys and then not obscure them when an app is in “anyone can view editor” mode. I mean, c’mon Bubble people. It’s almost like they don’t want anyone to teach anyone how to use Bubble. 
)