incorrect http hit ratio in stats

in my production, the proxy.node.http.cache_hit_ratio is always 0, it should be the same as proxy.node.cache_hit_ratio, that make my cluster wide stats error too:

[root@cache190 ~]# lynx -source http://localhost:81/stat/ | grep ratio
proxy.config.cluster.cluster_configuration=cluster.config
proxy.config.cluster.cluster_load_clear_duration=24
proxy.config.cluster.cluster_load_exceed_duration=4
proxy.config.icp.icp_configuration=icp.config
proxy.config.update.update_configuration=update.config
proxy.node.http.cache_hit_ratio=0.000000
proxy.node.http.cache_hit_ratio_int_pct=0
proxy.node.http.bandwidth_hit_ratio=0.904612
proxy.node.http.bandwidth_hit_ratio_int_pct=90
proxy.node.bandwidth_hit_ratio=0.904612
proxy.node.bandwidth_hit_ratio_int_pct=90
proxy.node.hostdb.hit_ratio=0.049913
proxy.node.hostdb.hit_ratio_int_pct=5
proxy.node.cache_hit_ratio=0.883374
proxy.node.cache_hit_ratio_int_pct=88
proxy.node.cache_hit_ratio_avg_10s_int_pct=93
proxy.node.bandwidth_hit_ratio_avg_10s_int_pct=93
proxy.node.bandwidth_hit_ratio_avg_10s=0.934583
proxy.node.cache_hit_ratio_avg_10s=0.930153
proxy.node.hostdb.hit_ratio_avg_10s=0.996169
proxy.cluster.bandwidth_hit_ratio=0.898589
proxy.cluster.bandwidth_hit_ratio_int_pct=1023958400
proxy.cluster.bandwidth_hit_ratio_avg_10s=0.938777
proxy.cluster.http.cache_hit_ratio=0.900161
proxy.cluster.http.cache_hit_ratio_int_pct=1063552512
proxy.cluster.http.bandwidth_hit_ratio=0.915798
proxy.cluster.http.bandwidth_hit_ratio_int_pct=1063552576
proxy.cluster.cache_hit_ratio=0.900161
proxy.cluster.cache_hit_ratio_int_pct=180
proxy.cluster.cache_hit_ratio_avg_10s=0.935070
proxy.cluster.hostdb.hit_ratio=0.047426
proxy.cluster.hostdb.hit_ratio_int_pct=6
proxy.cluster.hostdb.hit_ratio_avg_10s=0.337434
proxy.process.cluster.configuration_changes=1
[root@cache190 ~]# traffic_line -r proxy.node.http.cache_hit_ratio
0.000000

in my situation:
proxy.node.http.cache_hit_ratio=0.000000
proxy.node.http.cache_hit_ratio_int_pct=0
should be same as:
proxy.node.cache_hit_ratio=0.883374
proxy.node.cache_hit_ratio_int_pct=88

there is some strange error in cluster too:
proxy.cluster.bandwidth_hit_ratio_int_pct=1023958400
proxy.cluster.http.cache_hit_ratio_int_pct=1063552512
proxy.cluster.http.bandwidth_hit_ratio_int_pct=1063552576
proxy.cluster.cache_hit_ratio_int_pct=180