My previous thread about this issue: viewtopic.php?f=17&t=125692

So after v2.5 I notice that device under Mikrotik CSS326-24G-2S+ no longer give IP address to certain device under it.

My diagram is something like :
Certain devices under Unifi AP and Unmanaged switch no longer get IP address from DHCP, but it works fine if I connect the device directly to the switch. I revert back to v2.4 and everything works again.