My previous thread about this issue: http://forum.mikrotik.com/t/ps4-suddenly-not-getting-ip-address-from-dhcp-after-i-update-my-mikrotik-switch-firmware-to-swos-v2-5/112284/1
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 :
pfSense -> CSS326-24G-2S+ -> Unifi AP
-> Unmanaged switch
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.