flows not removed from the switch when 80k flows configured

tested odl: Lithium RC1 June15 version

steps:
1 connect mininet, 63 switches,
2) runs the script
test/tools/odl-mdsal-clustering-tests/clustering-performance-test/flow_stats_stability_monitor.py --host 10.25.2.9 --auth --fpr 20 --config_monitor 750 --deconfig_monitor 200 --monitor_period 30 --flows 16000 --threads 5 --bulk-delete
3) once 80k flows configured, restart mininet

this is not replicable on demand, it happened once
after flows were deconfigured, 2520 were not removed from the switch

linux-gnu>./get-total-found.sh
Switch s1: 0 flows
Switch s2: 0 flows
...
Switch s19: 0 flows
Switch s20: 0 flows
Switch s21: 0 flows
Switch s22: 1260 flows
Switch s23: 0 flows
Switch s24: 0 flows
Switch s25: 0 flows
Switch s26: 0 flows
Switch s27: 0 flows
Switch s28: 0 flows
Switch s29: 0 flows
Switch s30: 1260 flows
Switch s31: 0 flows
Switch s32: 0 flows
...
Switch s61: 0 flows
Switch s62: 0 flows
Switch s63: 0 flows

Total: 2520

The switches with flows are mentioned in the log more times than usual switch

[odl@pce-guest32 distribution-karaf-0.3.0-Lithium-RC1-v201506150016]$ grep -r openflow:30 | wc -l
13
[odl@pce-guest32 distribution-karaf-0.3.0-Lithium-RC1-v201506150016]$ grep -r openflow:22 | wc -l
13
[odl@pce-guest32 distribution-karaf-0.3.0-Lithium-RC1-v201506150016]$ grep -r openflow:11 | wc -l
9

I have not foung anythong suspicious, please have a look why this happened