Repush dataLayer events that occurred before consent loaded.
Google Tag Manager over-rides the push() functionality of the dataLayer array, to create a queue that can be used to process events. One of the major benefits of this, is that events triggered before GTM loads will be processed when it does finally load.
This functionality does not exist for Consent Management tools however. If an event is triggered before the trust logic has loaded - it will be missed by the tracking.
Trigger groups can cover some use cases and it's worth checking to see if this can cover your use case first: https://support.google.com/tagmanager/answer/9164222?hl=en
Many use cases aren't covered however, for example if a tag is firing multiple times.
backTrack is a tag template that adds functionality to repush missed events into the queue after consent is provided, so that no events are missed.
Steps to implement/configure:
1- Create a tag utilising the template.
2- Set the tag to fire once per page (IMPORTANT).
3- Add a trigger to the tag, so that it fires on the first event with consent, see the example below for OneTrust.
4- Adjust the positive REGEX to match the events that you wish to repush. The default REGEX will ignore GTM specific pushes and most major consent tool pushes. It is highly recommended to prevent the tag from repushing consent events, as this could alter the consent status and cause major issues for your tracking!
5- (Optional) If you wish to prevent recursive merge for specific objects, change the setting to 'specific' and add the objects as a comma separated list. For example: ecommerce,products.skus. This will push a NULL value for the specific object before any event containing the object. If you wish to prevent recursive merge for all complex data types, it is recommended to use the _clear: true parameter in your original dataLayer pushes. This tag will then replicate this in the repush.
-N.B If the object is embedded, you must specify the entire path to the object.
6- Test that everything behaves as expected.