Messages don't work in views when rendered as a field in "fields" formatter
Create a view of messages, choose to show "Fields". Next add a field for "Message: Rendered entity" and there will be no output.
Likely this is an unimplemented interface where messages diverges from other entities. Maybe somebody knows a quick way to fix this without having to do tons of debugging...
Active
1.2
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It's likely this issue predates Contrib.social: some issue and comment data are missing.
To manage permissions to view messages you can use an additional module
https://www.drupal.org/project/message_ui →
But in your case, you are using the additional field "field_message_to" to check access, so you need this custom code.