Administer/Diagnostics page, check Client Association, and enter a Zebra MAC address in the box 'Debug log per client or AP MAC address', then Apply.
Run some testing with your Zebra, don't go too fast, but see if you experience a disconnect when roaming so it will be captured.
Back on the ZoneDirector, click the Save Debug Info button, and contact Tech Support to analyze the logs for that Zebra client activity.
Ruckus TSEs have internal "Merlin" debug decoder that is more inspective than just the Rowdy Support Site log analyzer tool.