We had a problem much like this several months ago. We finally found that the Chrome OS version at the time didn't work well with the Ruckus software and firmware. We updated Chrome OS and Software/ firmware on the ZD and APs. This solved the issue.
We are doing the same thing. We found that restricting Android also caught Chrome devices.Ruckus support told us to upgrade to Ver 188.8.131.52 and Chrome would be listed.Note: Chrome OS must be at Ver 50.xx or above.