can you upload information on the schema of the tables involved? For example, if you had SQL server generate CREATE scripts for the tables and upload them for me, I could replicate your situation at my end. Or, just backup your whole database if it's not too large/complex/confidential and upload the whole thing.
Some simple example of source and destination table contents before and after the operation would be helpful, too.
I'm sorry,After reviewing the question, I regret that I won't be able to assist you at this time.
I am opting out and opening the question up to other professionals here who may be able to help.