replying to mail goes to a different email address

Hi, We have an issue. When a user receives a mail from a user and replies, the reply goes to another person in the senders company. I see no rules in place to do this from my side. Example is below, my user is ukunz@InformationMosaic.com, when he replied to that mail it always goes to James.Scanlon@MAPLESANDCALDER.com. If he creates a new mail to Edward Miller, it will be James Scanlon that receives it. The full header information is below

From: Edward Miller <Edward.Miller@MAPLESANDCALDER.com>
To: James Scanlon <James.Scanlon@MAPLESANDCALDER.com>
CC: "Ulrich Kunz (ukunz@InformationMosaic.com)" <ukunz@InformationMosaic.com>,
                Sarah Comiskey O'Keeffe <Sarah.comiskeyokeeffe@maplesandcalder.com>


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From: Edward Miller <Edward.Miller@MAPLESANDCALDER.com>
To: James Scanlon <James.Scanlon@MAPLESANDCALDER.com>
CC: "Ulrich Kunz (ukunz@InformationMosaic.com)" <ukunz@InformationMosaic.com>,
                Sarah Comiskey O'Keeffe <Sarah.comiskeyokeeffe@maplesandcalder.com>
Subject: Re: any news re the call to Lavelle?
Thread-Topic: any news re the call to Lavelle?
Thread-Index: Ac76dPAinOK4ttCfRUSfUw+Sq1hyaQAjvNuQAAAJCSAAAMGK4AABtp0A
Date: Tue, 17 Dec 2013 09:53:58 +0000
Message-ID: <AC51FE95-CA97-49D7-B546-D42075557ABF@MAPLESANDCALDER.com>
References: <8459976109E78C4F9E98DE5FC5A4B0242EF6E930@SVM0906101930.mosaic.local>,<A02623900E076A40B6C2181DD2EBAEB1330D04E3@IEEXMB02.MAPLESANDCALDER.com>
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