Our website has a number of sub-domains and we are in the process of migrating from classical analytics to universal analytics. When we migrated one of our domain from classical to universal analytics, with google tag manager, it started creating two _ga cookies. One against our main domain and another against the subdomain which looked like following -
cookie 1 - _ga - GA1.2.9876543210.9876543210 - .mysite.com cookie 2 - _ga - GA1.3.9876543210.9876543210 - .subdomain.mysite.com
Now I understand that GA1.2 stands for main domain cookie and GA1.3 stands for subdomain cookie. But I could not find answers of my following two queries -
- Will this multiple cookie system create any problem in my data?
- Is there any analytical use of creating two cookies?
I tried to search in google and forums regarding multiple "_ga" cookies but could not find any reference.
I also tried to see other sites using UA but could not see any site which creates separate cookies for domain and subdomain.