[windows] Data lost in offline upgrade from 2.5.x to 4.0.0-4019

Test version: 4.0.0-4019
Test run: -t xdcr.upgradeXDCR.UpgradeTests.incremental_offline_upgrade,initial_version=2.5.0-1059-rel,replication_type=xmem,bucket_topology=default:1>2;sasl_bucket_1:1><2,upgrade_seq=src><dest,GROUP=INC_OFFLINE

Initial cluster in 2.5.0
Load 5000 items to default bucket and 6000 items to sasl_bucket_1
Offline upgrade to 4.0.0-4019
After warmup, data lost in both bucket

Expect 5000 items in default bucket. Actual 4988 items
Expect 6000 items in sasl_bucket_1. Actual 5888

$ ./cbstats.exe localhost:11210 all | grep items
curr_items: 2488
curr_items_tot: 4988
curr_temp_items: 0
ep_access_scanner_num_items: 0
ep_chk_max_items: 500
ep_diskqueue_items: 0
ep_items_rm_from_checkpoints: 1988
ep_total_del_items: 0
ep_total_new_items: 3988
ep_uncommitted_items: 0
ep_warmup_min_items_threshold: 100
vb_active_curr_items: 2488
vb_pending_curr_items: 0
vb_replica_curr_items: 2500

Administrator@guava-s10422 /cygdrive/c/Program Files/Couchbase/Server/bin
$ ./cbstats.exe localhost:11210 all -b sasl_bucket_1 -p password | grep items
curr_items: 2888
curr_items_tot: 5888
curr_temp_items: 0
ep_access_scanner_num_items: 0
ep_chk_max_items: 500
ep_diskqueue_items: 0
ep_items_rm_from_checkpoints: 1888
ep_total_del_items: 0
ep_total_new_items: 4388
ep_uncommitted_items: 0
ep_warmup_min_items_threshold: 100
vb_active_curr_items: 2888
vb_pending_curr_items: 0
vb_replica_curr_items: 3000