Getting value of an Evar as Unspecified in mobile
In my mobile application, when a user logs in, he/she is given a UserId, which I am capturing and sending with each page view within the application. A user can't browse the application without logging in, so UserId is always there. But in my analytics, I am seeing sometimes the value against UserId eVar as Unspecified. I tried breaking it down by Page, but it shows 0 records and when I am breaking the Page metric with UserId, then I am not seeing any UserId as Unspecified. I checked my code also, there is no instance when I am sending UserId without Page. How is it possible that UserId is sometimes Unspecified without any page getting captured? Also, this is specifically mobile app code and can't be used in Desktop or by hitting URL.
Sample code used for sending details,
const contextData = { userId: 'ABC' };
ACPCore.trackState('Login', contextData);