Sorry for the late update. I was quite upset with this router. I was trying not to do anymore testing on it. I should have return it for refund instead of taking the advise from Dlink tech support saying the problem will be fixed in the next firmware update. The first day I installed it, I encountered issue. Now one year warranty is expired, i stuck with it.
Going back to the problem.
I have updated the router firmware to the latest canadian version 1.10b07. I reset the router to factory default, then a power cycle it.
I manually entered all the network configuration then another power cycle.
I did not named any device or reserved any IP address until now.
On the home page of the router, Dlink smart plug will display correctly, some others devices will display correctly, but 70% of connected device will be displayed as either "unknown" or duplicated named device on the network. i.e. it could display you have 4 HP printers instead of only 1.
I can named up to 24 devices (no IP reservation) then the message "The maximum number of permitted DHCP reservations has been exceeded".
So I can verify that the problem is still there. Naming a device is the same as IP reservation
On top of that, the home page/router cannot truly tell you the number of connected devices on the network.
I have 37 devices connected onto the network. The home page can only display max 27 which i have seen so far.
But it is not always display 27 devices, most of time less it is than 27.
This create a problem if I want to add a new device on the network. It is because the new device NEVER appear on the home page, hence I would not know its new ip address. Therefore I cannot configure the new device via its web portal.
Luckily I can use a mobile phone apps LAN scanner to identify the new device ip address.
So far, Dlink tech support told me to DISABLE Smart Connect, QoS Engine.
It is because I discover random disconnection problem.