Transactional Replication - Insert after Delete not working

Answer as per my investigation:

Normally this error occurs when an UPDATE or DELETE statement is executed by the publisher for a primary key value and the record (against which UPDATE/DELETE executed) does not exist in the subscriber database.

There are multiple reasons that could cause this:

1. It could be someone or a process/apps deleted and inserted the data in subscriber db (while cmds are being applied). Review your subscriber security settings and check what process/apps are accessing the subscriber db.
2. Multiple publications connected to subscriber db. pub1 (deleted the data first) then pub2 tried to UPDATE/DELETE the data which could cause an error 20598.
3. Triggers on subscriber tables that could delete/insert/update the data.