When a user uses COS portal in any other language except for English and creates assets in this language, without adding the name in English, then only he/she can see it, but not others.
If he/she wants the assets to be visible to others also, then adding the name to the section for the English language is necessary.
For example:
1. Write Asset´s name
2. Click on the Globe icon
3. Write the name in the field for the English language
4. Click on "Save"

So, the asset names which are not visible need to have a name entered in the field for English as well.
To avoid such cases, please set the System language in the user account to English.