gas forms in beer line

[Moog]

I notice that when I pour off some beer from my keg, using a pluto gun, soon after I stop pouring, you see gas forming in the looped tube. I'm pretty sure its only co2 coming out of solution, but why does it, surely it's all at the same pressure, so why does it come out?
It seems to make the start of the next pour foamy, until it clears.
Is there any way to not get this gas coming out?

 

[dkril]

Gas solubility depends on pressure and temperature. So even though the beer in the line is at the same pressure, as its temperature rises some of the co2 will come out of solution.

Only solution is to keep your line cool.

 

[Moog]

the line is cool, the tube, and pluto gun live in the fridge, its all at the same temp.