Missing items with Swap Rebalance

Build : 5.0.0-1917 onwards

Changelog : http://172.23.123.43:8000/getchangelog?rel=5.0.0&fromb=1916&tob=1917

The sanity test swaprebalance.SwapRebalanceBasicTests.do_test is failing in the verification phase while trying to count the number of items post swap rebalance. There are some missing items.

From testrunner console log :
[2017-02-07 22:12:21,741] - [rebalance_helper:362] INFO - curr_items from 172.23.106.140:8091 : 307
[2017-02-07 22:12:21,741] - [rebalance_helper:367] INFO - vb_pending_num from 172.23.106.140:8091 : 0
[2017-02-07 22:12:21,741] - [rebalance_helper:372] INFO - vb_active_num from 172.23.106.140:8091 : 342
[2017-02-07 22:12:21,741] - [rebalance_helper:377] INFO - vb_replica_num from 172.23.106.140:8091 : 342
[2017-02-07 22:12:21,742] - [rebalance_helper:362] INFO - curr_items from 172.23.107.132:8091 : 309
[2017-02-07 22:12:21,742] - [rebalance_helper:367] INFO - vb_pending_num from 172.23.107.132:8091 : 0
[2017-02-07 22:12:21,742] - [rebalance_helper:372] INFO - vb_active_num from 172.23.107.132:8091 : 341
[2017-02-07 22:12:21,742] - [rebalance_helper:377] INFO - vb_replica_num from 172.23.107.132:8091 : 341
[2017-02-07 22:12:21,742] - [rebalance_helper:362] INFO - curr_items from 172.23.107.133:8091 : 336
[2017-02-07 22:12:21,742] - [rebalance_helper:367] INFO - vb_pending_num from 172.23.107.133:8091 : 0
[2017-02-07 22:12:21,743] - [rebalance_helper:372] INFO - vb_active_num from 172.23.107.133:8091 : 341
[2017-02-07 22:12:21,743] - [rebalance_helper:377] INFO - vb_replica_num from 172.23.107.133:8091 : 341
[2017-02-07 22:12:21,743] - [rebalance_helper:380] INFO - summation of vb_active_num : 1024 vb_pending_num : 0 vb_replica_num : 1024
[2017-02-07 22:12:21,743] - [rebalance_helper:382] INFO - sum : 952 and sum * (replica_factor + 1) (2) : 1904
[2017-02-07 22:12:21,818] - [rebalance_helper:385] INFO - curr_items_tot from master: 1910
[2017-02-07 22:12:21,819] - [rebalance_helper:400] INFO - Nodes stats are: [u'172.23.106.140', u'172.23.107.132', u'172.23.107.133']
[2017-02-07 22:12:21,819] - [rebalance_helper:404] INFO - delta : 6 missing_percentage : 0.0031512605042 replica_factor : 1

This test fails consistently on and after build 5.0.0-1917 on all platforms. It passes with 5.0.0-1916.

Attaching logs from build sanity on Centos7 from 5.0.0-1919