I just plugged a AP350 into my switch new out of the box. Default vlan and native vlan on AP is vlan 1 and vlan 1. I consoled in an changed the mgmt0 vlan to my AP mgmt vlan and the native vlan to my native vlan. I noticed that the interface did not pick up an IP from my dhcp server, used the default aerohive IP. I saved the ap config and reboot it and it got an IP after reboot.
So maybe depending how you have you vlans setup, maybe the default vlan or native vlan is causing some issues.
I assume you are trunking on the switch and have a native vlan set.
try making sure the switch vlan configuration matches your ap mgt0 setup, and see if that helps.
commands you can use to set the vlan and native vlan are
interface mgt0 vlan X
interface mgmt0 native-vlan Y
I set my switch port as trunked and assign a native vlan to the port. I do not make any changes to the AP. When I plug in the AP it is assigned and IP addresses and load the latest firmware and configuration file from HiveManger.