Electric Network Statistics duplicates entities those connected to both of merged netoworks

[Hares]

I have a boiler plant with 240 steam engines in a network separated with a circuit-controller power switch. 2 of these 240 steam engines are shared to the main network via a large power pole. When networks are connected, the network statistics window shows that there're 242 steam engines. I searched for these extra two for several minutes before I realized that they are "duplicated".

Screenshot:

[FuryoftheStars]

I believe that's this: 69769

[Hares]

I sincerely searched for the duplicates but didn't succeed.
Thx!