Warmup tests fail with missing replica items post warmup

test to repro :

./testrunner -i ~/imp_scripts/ini/simple-metaData.ini -t warmup.warmuptest.WarmUpTests.warmup_test,eviction_policy=fullEviction,stats_monitor=vb_replica_perc_mem_resident;vb_active_perc_mem_resident,items=20,dgm_run=True,is_partial=True

Error:
======================================================================
ERROR: warmup_test (warmup.warmuptest.WarmUpTests)
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Traceback (most recent call last):
File "pytests/warmup/warmuptest.py", line 245, in warmup_test
raise Exception("Warmup check failed. Warmup test failed in some node")
Exception: Warmup check failed. Warmup test failed in some node

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Active items > Replica items, some replica items are always missing

root@mulberry-s10718:/opt/couchbase/bin# ./cbstats 172.23.106.235:11211 -b default all | grep vb_replica
vb_replica_curr_items: 2078
vb_replica_eject: 0
vb_replica_expired: 0
vb_replica_ht_memory: 1606144
vb_replica_itm_memory: 1735890
vb_replica_meta_data_memory: 193890
vb_replica_num: 64
vb_replica_num_non_resident: 0
vb_replica_ops_create: 2078
vb_replica_ops_delete: 0
vb_replica_ops_reject: 0
vb_replica_ops_update: 2221
vb_replica_perc_mem_resident: 400
vb_replica_queue_age: 0
vb_replica_queue_drain: 4299
vb_replica_queue_fill: 4299
vb_replica_queue_memory: 0
vb_replica_queue_pending: 0
vb_replica_queue_size: 0