Fermenting Started Again?

[ComcastWineRookie]

I have a question, I am making an imperial IPA and on tuesday I transferred to the secondary to dry hop, and starting last night I started getting bubbling thru my airlock again, is this normal? it fermented quick in the primary, I gave it 3 days after it pretty much stopped, and now its back bubbling every 10-15 seconds again 3 days after putting it on the hops. any explanations?

 

[wailingguitar]

The act of moving it caused dissolved CO2 to come out of solution, pretty normal