In my application, I am logging User IDs of users logging in with the Page Name. Logging in is mandatory for accessing the site, so post login only, a user can move to subsequent screens. In few instances, I am getting User IDs as Unspecified, I tried breaking it down on various dimensions, and got the below results,
Page - Unspecified
Mobile OS - iOS
Custom Link - ADBINTERNAL:Lifecycle
If I change the metric to Custom Link Instances, then the number of occurences against Unspecified matches with that of Custom Link Instances. In android, I am not getting Unspecified Instances. I found a similar thread here.
As the above thread is a bit old, just wanted to check is there a way to avoid these Unspecified instances? Or is it an expected behaviour? Also, why am I not seeing similar results in Android?