updating fields to set in GTM from dataLayer pushed variables

Question

I'm having an issue with updating values in the "Fields to Set" section of Google Tag Manager for event parameters in GA4.

I'm using GTM to send data to GA4, I have a configuration tag in GTM where I'm using the "Fields to Set" section to assign global values to event parameters. These values are pushed to dataLayer and updated at which point an even triggers to have the config tag reload the values.

I can confirm that the dataLayer is being updated correctly, When the values are updated in the dataLayer, I trigger the configuration tag to fire, which I can see in the GTM debug mode this seems to be working just fine.

However, even though the GTM debug mode shows the correct updated values in the fired tag, all of my events still shows the initial values for the event parameters.

I've tried to troubleshoot the issue but haven't found a solution yet, there isn't much information that I could find relating to fields to set online.

I'm wondering why the updated values in the "Fields to Set" section are not reflected in the GA4 event parameters. Is there something I'm missing or any additional troubleshooting steps I can take to resolve this issue?

Any help or insights would be greatly appreciated. Thank you!

Confirmed that the dataLayer is being updated correctly, When the values are updated in the dataLayer, I trigger the configuration tag to fire, which I can see in the GTM debug mode this seems to be working just fine.

Confirmed GTM debug mode shows the correct updated values in the fired tag, all of my events still shows the initial values for the event parameters.

Answer 1

Subsequent configs may not actually change the event parameters set with the initial one. See this for more details: can GA4 custom dimensions be updated after the initial 'config' call?

Your debugging is not full though. Besides looking at the GTM Preview, you should also pay attention to the collect network calls and what's actually being sent with tracking. It's important since this would distinctly indicate whether the issue is in your front-end or on the GA side.