Blinking Exit Signs

[electricalist]

Capacitance is more common in mwbc . In some cases degredation of wires. The 0 v wire acts as a capacitor storing energy from 1+v wire. Adding resistance to 1+v circuit will equally increase capacitance on the 0 v circuit..
Which seems similar to the statement the more lights connected the brighter the exits....

 

[cadpoint]

Besides all the great suggestions you could also have a miss wired circuit inside
the multi-wire circuit done at the time it was manufacture!