Secondary fermentation oddity

[gibbon]

Having completed fermentation of a Belgian Blonde, I decided to bottle most of it for consumption and experiment with the remaining couple gallons in small secondaries with fruit. In one large bottle I put a mixed berry blend, and then split an identical amount into two other bottles with blueberries. The two blueberry bottles are identical: same growlers, cleaned and sanitized at the same time, even the same stoppers and airlocks. I split the same batch of blueberry purée into each bottle. 48 hours later, one of them has been bubbling fairly consistently, and the other hasn't budged. Any thoughts?

The other bottle (with the mixed berries) is also bubbling slowly.

Curious to see what folks think...

 

[davekippen]

Loose air lock/bung?

 

[pdxal]

Loose air lock/bung?

+1
Also, is one in a warmer spot than the other?

 

[gibbon]

Rechecked the stopper and airlock, and both appear tight. Both are sitting next to each other, out of direct light and away from any heat source.

Strange, right?

The other bottle appears to be done bubbling at this point.

 

[lowtones84]

The yeast just like one more than the other.

 

[helibrewer]

Did you re-pitch at all? Any movement of gravity in the "calm" batch?