Carbonaton in secondary?

[budrockdiesel]

I have a Pale Ale that started out at 1.05.
Used a quart of starter. It bubbled after 3 hrs and continued for 5 days.
Racked after 8 days. I checked with my wine thief (1.015) and I had some small bubbles rising in the wine thief. It looked kind of like carbonation. I am also bummed because I added an extra lb of malt to try to bring up the my readings and it looks like it might be done.

 

[mmb]

In a way it is carbonation. That's the CO2 that the yeast release, along with alcohol, when it processes the sugars in the wort. Since the secondary isn't a pressure vessel your beer "off gasses" the CO2.

1.050 to 1.015 is a 69% apparent attenuation. Depending on what yeast you used and a few other factors like recipe and temperature that isn't too bad.