Welcome to Airtable Community! :slightly_smiling_face:
When you link a table to another table, a new field is created automatically in the table that is being Linked. In case you have any Hidden Fields in that table, this newly created field becomes hidden too.
I suggest you look at the fields list for a hidden field with the same name of the table in the 1st screenshot, this is were you will find your records.
If this helps, please mark it as Solution so others can see it.