I believe it is a CCBReader bug. There is an open issue about it in the CocosBuilder github page (https://github.com/cocos2d/CocosBuilder/issues/121). It should be fixed in the latest version of CocosBuilder + CCBReader, however, if you want to use the 2.1 version you can change the "sequenceCompleted" method of CCBAnimationManager to the following:
- (void) sequenceCompleted
{
NSString *completedSequenceName = [runningSequence.name copy];
int nextSeqId = runningSequence.chainedSequenceId;
runningSequence = NULL;
if (nextSeqId != -1)
{
[self runAnimationsForSequenceId:nextSeqId tweenDuration:0];
}
[delegate completedAnimationSequenceNamed:completedSequenceName];
[completedSequenceName release];
}