After implementing Mixpanel in my application, I checked the auto generated distinct id in browser by calling mixpanel.get_distictid(). It is always same even if, after refresh. This is a normal behaviour. But this is happening only with my localhost application. When I host this application to GCP app engine, the same function started returning different distinct id whenever I refresh the page and hence different users under my Mixpanel analytics reports.
Best answer by fredl
My first instinct is checking different browsers and see if it isolated only to one browser. Another would be how you are calling identify, are you only calling it when a user logs into your app?
I also found this article on tracking across hosted sub domains, it focuses more on Heroku but it can be helpful for you as well.