We are having the same issue except we are running 5 of the CK3X units. The issue is very sporadic for us. I can ping a device for several hours and never drop a packet. And not all packet drops result in an application lockup.
We have a 1/2 dozen Intermec CK71 connecting to HP 410 and 430 AP's that are controlled by a HP MSM730 controller. I have Wireless Mobility and Fast Wireless roaming enabled. Using Funk security on CK71 and it's at some rev of 1.50 firmware. We use Epicor's handheld module were the CK71's RDP into a Windows server and they run the handheld program.
We are having issues were the Epicor App freezes and I was fairly sure it was the CK71's losing wifi connection. I walked around with CK71, my android phone, and my Fluke Wifi Tester all pinging the same internal IP address, using the same SSID and settings. The phone and the Fluke never dropped a ping. The CK71 would drop up to 10 pings when it transitioned from one access point to the next.
Is this just a thing with these CK71's, would a firmware update to 1.6 (whatever) help this. The WIFI network was provisioned on the thin side but everything else is getting passed from AP to AP with no ping loss. Would adding more AP's help.
I did this same test at a different location with the same HP controller, AP's and phone, Fluke tester and same CK71. This other location's wifi network is provisioned a littler more robust, but the CK71 would drop pings there as well, just not as many.
Sorry I cant be much help, we have yet to deploy our 71's to the floor and haven't yet tested across ap's. We are running ver 1.61 though.
On your "robust network" test, did you experience freezing there as well?