I just installed c3560cx-universalk9-mz.152-7.E5.bin on the WS-C3560CX-12TC-S and I am getting this bug too. The workaround to execute "no ip cef optimize neighbor resolution" worked. Today is 17MAR2022.
Just asking another FlexConnect question since we are on the topic:
I have 5 sites with their own WLC 5508 controller. I will like to use FlexConnect to downgrade to only one WLC that provides for LAPs in all 5 locations. The question is, what happ...
Be careful when applying 8.3 updates. Many APs will only work with 8.0.x. Read the notes for supported APs before applying any updates or you will lose half of your wifi AP's.