movement of 27 empty replica vbuckets gets stuck in seqnoWaiting

Rebalance of 10 empty buckets never finishes.

Rebalance of first bucket ("bucket-10") completed successfully.

Movement of 27 vbuckets in bucket "bucket-9" started but obviously makes no progress.

451, 455, 459, 463, 467, 471, 475, 479, 483, 487, 491, 495, 499, 503, 507, 511, 811, 815, 819, 823, 827, 831, 835, 839, 843, 847, 851

According to master events the last step in all cases is seqnoWaitingStarted:

{u'node': u'ns_1@172.23.96.13', u'bucket': u'bucket-9', u'pid': u'<0.19962.2>', u'ts': 1405841984.068374, u'chainBefore': [u'172.23.96.13:11209', u'172.23.96.11:11209'], u'chainAfter': [u'172.23.96.14:11209', u'172.23.96.11:11209'], u'vbucket': 851, u'type': u'vbucketMoveStart'} {u'bucket': u'bucket-9', u'state': u'replica', u'ts': 1405841984.069871, u'host': u'172.23.96.11:11209', u'vbucket': 851, u'type': u'vbucketStateChange'} {u'bucket': u'bucket-9', u'state': u'replica', u'ts': 1405841984.070029, u'host': u'172.23.96.14:11209', u'vbucket': 851, u'type': u'vbucketStateChange'} {u'node': u'172.23.96.14:11209', u'bucket': u'bucket-9', u'vbucket': 851, u'type': u'indexingInitiated', u'ts': 1405841984.073599} {u'bucket': u'bucket-9', u'vbucket': 851, u'type': u'backfillPhaseEnded', u'ts': 1405841984.074577} {u'node': u'172.23.96.14:11209', u'seqno': 0, u'bucket': u'bucket-9', u'ts': 1405841984.075081, u'vbucket': 851, u'type': u'seqnoWaitingStarted'} {u'node': u'172.23.96.11:11209', u'seqno': 0, u'bucket': u'bucket-9', u'ts': 1405841984.075081, u'vbucket': 851, u'type': u'seqnoWaitingStarted'}

Not surprisingly 1051 replica vubckets are reported.