Hi mate,
It seems possible issue of layer 3 roaming.
Do you have Fast Roaming enabled?
Check if mobility configuration on that SSID is supports layer 3.
It would be a good indication if you run a "Debug client <mac address>" as it will show you if the process was reassociation or reauthentication.
This would be a good reference.
https://www.cisco.com/c/en/us/td/docs/wireless/controller/8-5/config-guide/b_cg85/overview.html
Cheers,
Raffy