Hi there, 

I have recently added a checkbox field to the person entity which acts as a flag to indicate a person is eligible for an upcoming MailChimp campaign. When creating a group for sending to MailChimp, if I add the checkbox field to the search criteria, I get no results (regardless of whether it is a static or dynamic group). If I add the checkbox field to the advanced find, it works. 

Is this a bug or am I missing something in my logic?

Any advice would be greatly appreciated,

Paul