We did a trial set up of setCustomerID for our site.
However, when user logs in I can see it listed twice in the image request. When user logs out this parameter is missing. I would assume that as soon as user logs in this parameter becomes persistent like Marketing Cloud ID. I can see that in our case it works differently. Could you please tell me what needs to be corrected. Thanks.
To clarify my response, once a setCustomerID call is made with an authentication state of authenticated, the Customer ID is associated with the 'mid' used in Analytics. This allows you to view various reports in analytics associated with the ID like Customer Attributes. If you wish to use Target to act on this ID, the ID will need to be set on each page and must be set to authenticated for Target to take action.
Did you still need additional assistance with your original question? If not, is there a reply that we can mark as correct in case others view this post?
I'm not familiar with Target Profile Scripts. I haven't heard of doing that so I'm going to say it's unlikely, but you can always try it in a staging environment. You could also post the question on the Target community to see if anyone over there has had any experience.
The CustomerID variable is not persistent. It needs to be set on each page along with the authentication state. This allows the various Adobe solutions to use the variable properly.
As for the first image request having two customerIDs, you may have an implementation issue. Can you tell me how you are implementing the MCID service and the setCustomerID function? Are you deploying via DTM, AEM, or page code?