When migrating any AP whether it's from ZD to SCG, Unleased to ZD or SCG etc etc the AP requires to be factory reset after new firmware is pushed to the AP due to RPM key issues.
Process would be as follows:
1. Change firmware on unleashed to Base 100.
2. Factory Reset.
3. Enable discovery agent:
set discovery-agent enabled
4. Set director IP if required - only required if AP is doing layer 3 migration
5. Set lwapp MTU to 1250 - helps mitigate AP provisioning loops on layer 3 networks
5. As a precautionary method set NTP on AP:
set ntp server x.x.x.x
set ntp server update
Good luck