It is a record that I created manually as a test, by pressing "New" button in the CI table, not something created by the discovery.

Did you add the custom CI class to the "List of CI Types to Pattern" in the pattern Designer?

You can open this by clicking on the button next to the ci class dropdown list..

Yes, already added as shown below

Hi @Au_an 
I came across this while trying to fix a similar issue.  Mine was due to creating a new CI class and pattern in one instance, and migrating it to another instance.
The pattern I created works in the source instance but not the one I migrated to.

I found that the target instance was missing a cmdb_class_info record for the new class I created.  Migrating this record from the source instance fixed my issue.
If you've only been working in a single instance, perhaps just check if there is a cmdb_class_info record for your new class, and if there isnt create one.