I still have some doubts, let's take the below example:
I have 100 users who would visit my website, I have two variations to show - A and B. There's a chance that based on user_id/device_id hash - majority of hash values are generated <0.5 on 0 to 1 scale while my rule says 50% of users should see variation A and another 50% should see variation B. This is a discrepancy.
GrowthBook app should be able to record data about how many users are being served variation A vs variation B but I don't see any such network call with Javascript sdk since the evaluation is on SDK side and no POST call to GB app afterwards.