ifconfig -alias panics RPi3 kernel when called from this section of dhclient-script
eval "$IFCONFIG $interface inet -alias $old_ip_address $medium"
per Diane Bruce
Collecting additional information and hope to be able to duplicate this locally.
This is the second bug mentioned in PR 228929
Created attachment 194230 [details]
RPi3 panic during dhclient
The dhchpd server is set to always return the same address to this RPi3. I can experiment with that turned off later today if needed.