google analytics - utm_source and utm_medium gets lost in SPA

Question

I've got a weird problem with my SPA application and analytics. The source/medium parameters are being lost during the session for some users.

I'm using the history API using Google Tag Manager as recommended, and it works. But for approximate 30% of the users loose their utm parameters and becomes referrals. I don't understand this behaviour, anyone seen this before?

So, I know that 100% are

(source/medium) = mySource / affiliate

but looking in analytics, approximately 30% are loosing their utm parameters and it becomes:

(source/medium) = mySource / affiliate (70%)
(source/medium) = mysource.com / referral (30%)

Any suggestions? I'm a bit lost right now.

Answer 1

As the sites is a Single Page Application (SPA), you are most likely facing the problem of 'Rogue Referral'.

If this is the case, what happens, is that you overwrite the location field in the Analytics hit, losing the original UTM parameters, whereas referral is still sent with the hit, so Analytics recognizes the second hit as a new traffic source. One of the solutions is to store the original page URL and send it as the location, while sending the actual visited URL in the page field.

A very good article on this topic with further tips, by Simo Ahava, is available for your help.