You could also create a process plugin to create the Paragraph inline with the record you are migrating. I can't do piecemeal migrations in my case. The project has about 100,000 nodes and no data structure to 'create' Paragraphs out of. Even if I could, I don't want to have to run that dozens of times to get a full set of data.
Here is a real ...
I was able to accomplish this by creating a custom process plugin for the address field.
The following basically means
use the default process plugin get to look for a source column or constant named menu_link_content to determine the value for bundle.
which most likely returns null.
Try setting it with the default_value plugin instead:
I got the same error when porting Drupal 8 to localhost.
In my case I found a solution visiting mysite/core/install.php location.
There I saw a detailed error: when backing up from /admin/config/development/backup_migrate some tables were missing. So I backed up full database from phpmyadmin, and problem was solved.