I can repro this on my test site (which is production). I think it’s mainly a UI thing as the ‘warning’ is actually telling you you need to refresh the page to load in the new tab. The red makes it seem more intense though. 
It does seem like there may be a missing translation as well.
Let’s merge these into it so we’re not cross-posting the issue in multiple places. 
This I can’t replicate. When I refresh the page the warning goes away, and the data explorer tab is now on-screen.