Issue

When attempting to modify mapping within a newly created Google Ads Conversions destination in Twilio Segment, you may notice the Map Fields section of the default mapping (named Session Attributes Encoded Plugin) appears locked or non-configurable. It displays the source and destination but does not provide options to map, edit, or customize individual fields.

Product

Twilio Segment

Environment

Segment Console

Cause

This behavior occurs when attempting to modify the Session Attributes Encoded Plugin mapping. This is a default, pre-built infrastructure mapping automatically added by Segment upon destination creation, or when selecting the Session Attributes Encoded Plugin action when creating a new mapping. By design, this specific system mapping does not contain or allow user-configurable field options.

Resolution

1. Open your Segment Workspace and go to Destinations.
2. Select your Google Ads Conversions destination.
3. Click on the Mappings tab.
4. Click the New Mapping button.
5. Select the desired conversion or tracking action from the available options (for example, Upload Click Conversion or Upload Conversion Adjustment).
6. In the configuration screen for the new mapping, scroll to the Map Fields section, which will now be fully available.
7. Map your source properties to the destination fields as required, then save and enable the mapping.

Additional Information 

A preview of the available actions and their associated fields can be referenced in the Google Ads Conversations destination documentation.