APIPA for some users

Every now and then some users will not receive the correct dhcp address when connecting to a wpa2 enterprise ssid. This ssid is bridged with another vlan for physical ports under end users desks. DHCP is handed out by the fortigate, so no relay server. Users will have a dhcp lease assigned in the fortigate but when checking WiFi clients it shows them with a 169.254 ip address and doesn’t allow them to connect via WiFi. Logs show discover and offer but no ack. The next day these users will be able to connect just fine but then this problem randomly happens again. Not sure what would be causing this issue. Any suggestions would be greatly appreciated. Thank you!