@JohnThere 

What you are saying is twice in 3 months your home network DHCP server went down or was not accessible. This is what triggers Smart DHCP in Deco. There are also other types of networking devices that have same functionality. So, if Smart DHCP is disabled in Deco, perhaps it is some other device starting its DHCP service when DHCP server goes down.

The true fix is to find why your network loses its DHCP server (even if briefly) and correct that.

From what i notice, is that the gateway of all my devices is pointed to DECO itself. And also from the Deco app from the Online clients. Almost all endpoint devices that are wired are connected. Which means it's the Deco itself sending those DHCP.