Mention user under custom field doesn't create profile link (mention) for users created after GDPR changes

Issue Summary

When a custom field 'User Picker (multiple users)' has users created after GDPR changes (having user key on JIRAUSERXXXXX format), Automation is not able to mention all users from the field.

Steps to Reproduce

Jira Software 8.22.1
Automation for Jira 7.4.2

1. Create an action to comment or send an email
2. Using the following smart values to mention who's under a 'User Picker (multiple users)' custom field: i.e. Approvers field:

   Hi {{#issue.Approvers}}[~{{accountID}}]{{^last}} & {{/}}{{/}}
   Hi {{#issue.Approvers}}
   Hi {{issue.customfield_10207}}
   Hi {{issue.customfield_10207}}{{^last}} & {{/}}{{/}}
   Hi {{#issue.Approvers}}[~{{displayName}}]{{^last}} & {{/}}{{/}}
   {{issue.Approvers.name}}
   
   If the custom field has only one user, the mention works using the following smart values:
   [~{{issue.Approvers}}]
   [~{{issue.customfield_10207}}]
   

Expected Results

The output should mention each user included in the custom field.

Actual Results

Automation only mentions when there is a single user in the field and/or when the users have a username as a user key instead of JIRAUSERXXXXX 

Workaround

Using name
i.e.

{{#issue.Approvers}}[~{{name}}]{{^last}} & {{/}}{{/}}