Gateway IP disappears from wireless user pc arp table

[chan4261]

Gateway IP disappears from wireless user pc arp table

Wireless users in an SDA environment are intermittently disconnected from the network. 
When I checked, the SSID was connected, but communication with the gateway was not possible.
And i checked with the Arp-a command on my PC and the gateway Arp does not appear.

controller is C9800-L-F-K9 using Version 17.6.5, AP is C9120AXI-K

[Haydn Andrews]

TAC recommended versions are 17.9.5 and 17.12.3. Recommend to upgrade to one of these two versions and see if issue still there

https://www.cisco.com/c/en/us/support/docs/wireless/catalyst-9800-series-wireless-controllers/214749-tac-recommended-ios-xe-builds-for-wirele.html 

[chan4261]

Thank you for your reply, the upgrade will be available soon.
Also, I am using NAC solution and have Arp flooding set up on the backbone switch. Is this related to the issue?
NAC is using Genian NAC 

[Rich R]

Also take note of https://www.cisco.com/c/en/us/td/docs/wireless/controller/9800/technical-reference/c9800-best-practices.html#AddressResolutionProtocolARPproxy