We are experiencing the same error message when we try to click on a PDF link in a user's profile that they've uploaded into a file field.
We're using CB 2.1.3+build.2017.09.13.16.14.19.ba9d1f686 and Joomla 3.8.1.
The error message doesn't read like a permissions issue. It reads as if there's a plugin disabled or new setting that needs to be enabled.