We are currently experiencing a very strange issue on our WiFI network. We have a ZD 3000 and R510 AP's. It appears that the clients on Vlan 3 cannot see any AirPrint devices when there are a certain unknown number of clients connected to that particular AP. Once the number of clients connected to that AP reduces the AirPrint devices become visible again. All clients are BYOD MacBooks or iPads and they authenticate using Cloudpath.
As an example 15 Vlan 3 clients are connected to AP1, 5 (mixed Vlan) clients on AP2, Both AP's connected to same switch, clients on AP1 cannot see any AirPrint Printers. If a Vlan 3 client from AP1 roams to AP2 the AirPrint printers appear.
Client Isolation is disabled on the Wlan and Bonjour Gateway is configured correctly and as I stated it works perfectly fine as expected when there are just a few devices connected to the AP. The issue only occurs when the connected device count increases.