Thats how Wifi works. Like how Mazunga explained its basically exactly what it is.
Wifi has different channels ever 100 degress celcius. If you are unsure whether some are linked or not you can press 7 and hover over one, it shoudl show a line connecting the wifi in the same channel. You can also see the channel with tmp, every channel has a corresponding tmp number.
ive had the same problem, they only seem to differntiate if you change the sign (EX: -30 and 30 would not trigger eachother)