Overview:
Smart Linking to view a record of the custom object in MyInsights is not working properly.
Root Cause:
This is because the custom object has _vod extension in the API name.
Solution:
Change the custom object's API name by removing the _vod extension.
Once this is done, the Smark Linking works fine for viewing the custom object.
Related Documentation:
CRM Help Documentation: Smart Linking in MyInsights