access scanner is not running

I am running a test runner test which among other things verifies that access scanner runs by monitoring the stat ep_num_access_scanner_runs - we see that this stat is always 0 when waiting up to 120 seconds.

The failure is seen on build 1854, this test passed on build 1673.

The test runner test command is:
python ./testrunner.py -i ~/servers/tunable-vms1234.ini max-dupe-result-count=10,get-cbcollect-info=False,num-tries=60,attempt-num=60,get-delays=True,GROUP=P0,eviction_policy=fullEviction,dgm_run=true,bucket_size=256 -t warmup.warmuptest.WarmUpTests.warmup_test,stats_monitor=vb_replica_perc_mem_resident;vb_active_perc_mem_resident,items=20000,replicas=2,active_resident_threshold=80,dgm_run=True,is_partial=True,doc_ops=expire

Logs are attached. The test failed when the ep_num_access_scanner_runs stats for 172.23.106.24 were 0.. please let me know if there is more information I can provide