Most lighted switches use the lights being controlled to complete the circuit for the little lamp in the switch. Not enough current flows to make incandescent lamps in the main fixture glow but some current must flow, including through the ballast if the lamp is fluorescent. Sample to sample differences in CFL lamps being controlled by the switch can result in charging of capacitors in the lamp ballasts and flickering of just one of the lamps, the same one each time, which discharges the capacitors in all of the lamps. Then the cycle repeats.
OT: Neon switch lights require something like 70 volts to strike. Sometimes the characteristics of the lamps (some fluorescent or extremely low wattage incandescent) being controlled are such that fewer volts appear across the switch terminals with the switch turned off and the switch light does not come on.
If the switch light is neon and has not lit up, then the voltage across the main lights (to neutral) should be zero with the switch off and after any capacitors have discharged (screw an incandescent lamp into one socket for a few seconds). If the switch light is lit and uses the main lights to complete its circuit, then some voltage can be measured from the switched hot terminal of the switch (and also the hot terminal of the main lights) to neutral, how much depends on the specific lamps in the main light fixture.
Yes with the switch off the switch is lighted i will check into it thank s for that info AllanJ I can try a normal non lighted switch and see if i lose my 30 volts thank you AllanJ