Freeradius and memory usage

Hello, Our radius server is currently having some memory issue where its memory usage would increase by 1% every 30-45 minutes. Eventually the server will crash and restart because of out of memory. We've been using freeradius for a couple of years and this just started on Thursday so I upgraded our radius to the latest 2.1.6 from 2.1.5 but the problem still there. Has anyone ever experiencing this issue before? Cheers, Roy Kartadinata