Content database existing in Central admin but invisible in PowerShell Cmdlet

Hello,

I have a strange behaviour in my Shrepoint 2016:

I have an application working fine with its content database, in fact in the Central admin -> Application management -> Databases -> Manage content databases, the screen shows a correct association between the webapplication and the content db.

Also the application is correctly responding over the web.

Nevertheless if I try to get the application content databases from PS I get null (Get-SPWebApplication XXXX | select ContentDatabases)!

And also if I list the content databases from PS I don't get that one in the list (Get-SPContentdatabases | select name, WebApplication).

How is it possible? What can I do to fix the situation?

P.S. The farms hosts other webapplications/sitecollections too, but for those all OK: their content databases are correctly listed both in Central admin and in Powershell CmdLet

Thanks!