initial_utm gets overwritten
We are experiencing the following behavior:
1) A user signups to our webapp with no utm_source on the URL parameters
2) Our webapp sends the Identify event without including the utm_source attribute
3) The identify event travels to segment and amplitude as expected.. and also as expected the initial_utm_source is empty.
Then... imagine 3 days later we send an email to that user including a remarketing campaign link. The link points to the signup and on the URL parameters we include utm_source=remarketingCampaign1
4) As expected, our webapp sends an identify event again to Segment and amplitude
Under this scenario we would expect the utm_source of the user to get written to remarketingCampaign1 and the intial_utm_source should have remained emtpy.
HOWEVER, what really heppened is that the initial_utm_source changed from epty to remarketingCampaign1.. making us think that the user made his initial signup from that campaign and that is not the case.
QUESTION: is this how it should really work? are we missing something?
Maurizio Oneto thank you for writing in! Digging into the Amplitude docs, I believe this is the expected behavior on Amplitude's end. See the following link for reference
Amplitude can capture the initial UTM parameters and referrer information for each user. The first-touch attribution values are set when a user's non-null UTM parameters are seen for the first time. The following user properties are set once:
According to that information, the first time those values are seen, they will be forwarded to the initial fields in Amplitude.
Hope this helps to clarify it!