I have a message template that has a field named "field_issue". The issue is being assigned correctly. However, the token [message:field_issue:entity:title] doesn't get replaced. Are fields automatically included in tokens? I don't see any relevant code in the message.token.inc, so I think this might need work.
Expose all message fields as tokens in the standard Drupal way.
Include a token browser on the message template edit page.
Postponed: needs info
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It's likely this issue predates Contrib.social: some issue and comment data are missing.
Assuming in your example that field_issue is an entity reference field and that you have set that field in your message entity before sending; then that token should work as expected.