[system test][windows] ep_warmup_access_log is corrupted in warmup test

Environment:
9 windows server 2008 R2 64-bit (each server has 8 GB RAM, SSD storage)
10.3.4.127
10.3.4.132
10.3.4.133
10.3.4.134
10.3.4.135
10.3.4.136
10.3.4.137
10.3.4.138
10.3.4.139

Cluster setup:
7 nodes cluster installed couchbase server 2.5.0-1022
10.3.4.127
10.3.4.132
10.3.4.133
10.3.4.134
10.3.4.135
10.3.4.136
10.3.4.137

2 buckets:
sasl-1 with 1 replica, 1 doc with 1 public view
sasl-2 with 2 replica, 1 doc with 1 public view
Test step:
Load 20 M items with size from 128 bytes to 512 bytes into each bucket.
Do access phase in 3 hours
Do warmup test on node 137 (first test in system test).
After warmup finished, check warmup stats, see ep_warmup_access_log corrupt in both buckets

$ ./cbstats.exe 10.3.4.137:11210 raw warmup -b sasl-2 -p password
ep_warmup: enabled
ep_warmup_access_log: corrupt
ep_warmup_dups: 1327893
ep_warmup_estimate_time: 52694
ep_warmup_estimated_key_count: 11460849
ep_warmup_estimated_value_count: 11460849
ep_warmup_item_expired: 5338274
ep_warmup_key_count: 11460849
ep_warmup_keys_time: 616003056
ep_warmup_min_item_threshold: 100
ep_warmup_min_memory_threshold: 100
ep_warmup_oom: 0
ep_warmup_state: done
ep_warmup_thread: complete
ep_warmup_time: 794502766
ep_warmup_value_count: 3844876

Administrator@WIN-4QPNIHRQT8M /cygdrive/c/Program Files/Couchbase/Server/bin
$ ./cbstats.exe 10.3.4.137:11210 raw warmup -b sasl-1 -p password
ep_warmup: enabled
ep_warmup_access_log: corrupt
ep_warmup_dups: 16
ep_warmup_estimate_time: 35884
ep_warmup_estimated_key_count: 7916708
ep_warmup_estimated_value_count: 7916708
ep_warmup_item_expired: 33
ep_warmup_key_count: 7916708
ep_warmup_keys_time: 100350953
ep_warmup_min_item_threshold: 100
ep_warmup_min_memory_threshold: 100
ep_warmup_oom: 0
ep_warmup_state: done
ep_warmup_thread: complete
ep_warmup_time: 232562289
ep_warmup_value_count: 6419189