Whisper count.wsp files are missing


I have a logstash configuration using metrics of the below form;
meter => [ "%{component}.%{host}.%{http_api}.%{http_status}" ]
For example:
component,host,http_api,http_status from my dataset will be

When i use a single metric plugin using a meter as show above, things work perfectly. I get the right numbers for http_status (count, rates..) etc and able to send to graphite db.

However for an experimentation, I wanted to use multiple metrics to bring in different dimensions into graphite..
metrics {
meter => [ "%{component}.%{http_status}" ]
add_tag => "metric1"

metrics {
meter => [ "%{component}.%{http_api}.%{http_status}" ]
add_tag => "metric2"

metrics {
meter => [ "%{host}.%{http_api}.%{http_status}" ]
add_tag => "metric3"

When I execute logstash with multiple metrics as show above, I notice problems with whisper files getting created in the graphite backend. i.e For a http_status = "ERROR" i dont see any count.wsp files at all.. I dont know the exact reason at some levels I see the *.wsp files and at some level, they are missing. This was not the case when I used a single metric and meter.

Appreciate some insight to this problem and what I should be looking into next?
Is it something to do with carbon-cache configuration setting?