I get no errors

That is probably because you are using INSERT IGNORE, try without IGNORE

From the MySQL docs

If you use the IGNORE keyword, errors that occur while executing the INSERT statement are ignored. For example, without IGNORE, a row that duplicates an existing UNIQUE index or PRIMARY KEY value in the table causes a duplicate-key error and the statement is aborted. With IGNORE, the row is discarded and no error occurs. Ignored errors may generate warnings instead, although duplicate-key errors do not.

If the dbh2 and dbh3 connections are the same,you will be selecting and inserting records from the same table so duplicates are likely.

Use of uninitialized value $insert[2] in join or string at /home/rdsco
+py.pl line 108. 
Use of uninitialized value $insert[14] in join or string at /home/rdsc
+opy.pl line 108.
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Those warnings mean you are missing data for parent_id_code and queue_code. Are NULLs allowed in these fields ?.

poj