Reproducible in JIRA 5.2.4 but not reproducible in JIRA 4.4.5

Steps to reproducible:

1. create a select list with multiple Context. refer to Configuration.png
2. create same name value for some of the context. Eg: "sun" exist in multiple context
3. create issues with the value "sun" for issue in different project that use different custom field context
4. create a new dashboard
5. add a new Issue Statistic Gadget. Sort by Total as per shown in EditGadget.png
6. Issue Statistic gadget will have multiple "sun" that has same total issue:
   

This is not reproducible if the Sort By is set to Natural