Issue with User Identification and Event Merging in Unity3D Mixpanel

Hello. I have a question/issue on user identification. I'm on Unity3D platform, with lib version 3.5.3. I have created a fully new project to test this out, and select Simple ID version: The application starts, and the user has a random distinct ID (e.d. asdasd-asdasd-asdasd) I track a few events and see everything in the dashboard tracked well under that user. then I perform SignIn in the application and call mixpanel.Identify("with my id") (eg. 1234) then I track a few more events and see everything in the dashboard tracked well under that NEW user with id 1234. But the problem is that these 2 users are not getting merged even after a day. and when getting number of event of the user 1234, the events under "asdasd-asdasd-asdasd" are not included. what should I do( or do wrong?) thanks