We have noticed some inconstancies with the custom pie chart reporting.
Around 1/3 of our traffic was hitting our rule "other" for 0.0.0.0/0. We removed this rule since there will be a "slice" added for destinations not specified. However, the chart only reports about 1% of data not matching our existing rules, not the 1/3 that our other rule reported.
We are also having problems with subdomains. We have separate rules for sub.domain.com and domain.com as we want to measure this separate. For two services, we have about 20% of our traffic going to domain.com with less than .5% to sub.domain.com despite knowing the subdomain should be getting the majority of the traffic.