hello! what does the "Multiple Exposures Check" ac...
# ask-questions
hello! what does the "Multiple Exposures Check" actually mean under the hood? how can i track down what could be causing it?
we're terminating the session id in cdn and use vary headers + unique responses to cache all experiment+feature combinations uniquely
Hi Jonathan
usually its the result of using a different assignment attribute from the assignment id used in the reporting
i see, we load the sdk both in cdn and client side (for visual testing), maybe we have a mismatch there
so if you assign by session id, you'll get users who are exposed to multiple variations if their session expires/changes
ya, could be
i think we simply a cookie for the session id though, but i'll check
hi again Graham, we don't push the user id (a uuid) itself into the tracking, and we use gtm -> ga4 -> bq for reporting
does this mean our uuid isn't being sent into bq ultimately and therefore this is an issue?
Hi Jonathan, sometimes folks run into challenges when using custom IDs with GTM/GA4/BQ. Starting with this section in the docs and continuing for the 2 sections after it is more info about using custom IDs with Google. Could you send me a screenshot or code snippet of how you're generating and setting the ID, and how it's being passed to Google? This would be happening in the GrowthBook-related code within your application, most likely.
hi again @brief-honey-45610! i found that we generated a new ID on every request, a super clear issue that we resolved, but we're still getting it and it's difficult to figure out what's causing the mismatch error we're generating and terminating the error in a fastly cdn edge function and passing it to GB, and then it goes down to the frontend which experiments are viewed and we push those to GA4
we never push our own GB UUID to GA4, as i understood this shouldn't be required?
Hello @brief-honey-45610, Im a colleague of Jonathan, do you have an update to the question above regarding uuids?
Any updates on this one?