How to debug why some content is not migrated from D7 to D8? I am using migrate_plus to migrate from D7 to D8 and so far it has been a fairly smooth process.

I have a particular content type that has 10 nodes in D7 but will only migrate one of them to D8.

After running the migration, one node is reported to exist and is successfully migrated. There are no messages related to the migration so I don't have any issue to remedy, yet only one of the ten nodes are migrated.

Can anyone suggest a way to dig into why this might be happening and/or how to get the missing nodes to migrate?
This issue was due to not factoring in languages when migrating.
So if you have the same issue you'll probably need to look at your i18n migrations.