Conditions
Seen on version 16.12.3
This happens when you have FNF config under physical interface such as :
interface Port-channel4
ip flow monitor dat_Vlan2021_-768145074 sampler deterministic_1_32 input
ip flow monitor dat_Vlan2021_-768145074 sampler deterministic_1_32 output
Workaround
none, WLC crashes and reloads