Couple of suggestions...
1. You say you're using ADP. This is multicast based. Assuming this site is routed, is the multicast routing going to work all the way from the controller VLAN to the AP VLAN in question? Are you 100% the other APs in that VLAN aren't statically provisioned, and therefore not dependant on ADP?
2. If the AP is struggling to contact the controller, you should be able to ping it between boot cycles. Assuming you allow ICMP through the Juniper, can you ping it periodically, then it goes away, comes back ok? This should prove the unicast/routing path.
3. In the Juniper, can you see the DHCP lease for the AP, and does it align to the AP MAC correctly?
4. Assuming the switch type used to provision is the same as the one onsite, can you interogate the PoE draw/delivered on the AP port? What does it show? If the cable to the AP (on the wall or whatever) is new and not well crimped/made, you might be loosing PoE delivery potential down the cable, and the AP might not be able to get enough. I assume when you provisioned it, you did it with a shorter cable on a desk or similar into the switch. That won't have as much loss, so it's different.
Thanks.