I have an asset custom field (Contact (IF)) which can contain multiple values (Asset Objects).

I am trying to create a Jira automation rule to update the share_coverage attribute on each object using the existing values and adding new values, respectively.

The automation:

Currently, it is concatenating all the existing attributes and updating each object with the old concatenated values as well as the new values.

Instead of just adding REM to each object respectively.
Does someone perhaps know if there is a solution for this in Jira automation?