Originally Posted by JBC
My first question is that it appeared to stop completely after only a few days. I thought that activity would gradually decrease to the point that, even 14 days later, there would be minor activity.
My second question is its re-starting after I put it in the secondary.
Fermentations often appear stop completely after only a few days. The main event is over, but the yeast are still fermenting the last few gravity points and cleaning up by-products from fermentation (e.g., diacetyl).
The physical act of racking to secondary causes some CO2 to be released from solution which in turn makes the air lock bubble. I'd be surprised if it continued to bubble for very long.
Airlock activity is not a good indicator of fermentation activity. I've noticed that airlocks can bubble when the atmospheric pressure changes due to storms or fronts passing through. A hydrometer is the only way to know for sure if you're at or near your target final gravity.
EDIT: Ooops, I re-read the original post and I see you're not really a noob. You probably know everything I just said.