That’s because PieSync doesn’t sync deletions. It’s a safety measure on our end to avoid PieSync from being able to wipe out (parts of) their databases completely cross-connections/in multiple apps, when a manual error is made for example.
Once you delete a contact, PieSync will also not try to recreate said contact. The contact in the other app will become excluded.
PieSync does have the syncing deletions feature in some of their integrations. This tags the deletion from app A in app B. It will never automate hard deletes but this way you can check the 'trash' segment in app B and hard-delete manually after reviewing. We should be able to do this for most connections with Command.