Voltage gauge- is this normal?

[God]

When I turn my blinker on my voltage needle ticks back and fourth a notch or two in sync with the blinker speed. I think it's done it since I've owned my 97 Yukon the past couple years. Figured I'd ask if this is normal

 

[SunlitComet]

not really. sometimes the voltage reg can act up and do that or dirty ground connections/corroded connections.