lookup field (multiple value) more than seven values on copying from one library to another using extension method SPFileCollection.Add throws error

I have  a lookup field which is multiple value field. If I use less than seven values and copy from one library to another using extension method spfilecollection.add I do not face any problem.

However if I a use more than seven values in lookup field it throws below error

Microsoft.SharePoint.SPException: The URL 'Labinal_FrontOffice_Documents/Manufacture/MFG0701IN310F007.xlsx' is invalid. It may refer to a nonexistent file or folder, or refer to a valid file or folder that is not in the current Web. ---> System.Runtime.InteropServices.COMException (0x81020030): The URL 'Labinal_FrontOffice_Documents/Manufacture/MFG0701IN310F007.xlsx' is invalid. It may refer to a nonexistent file or folder, or refer to a valid file or folder that is not in the current Web. at Microsoft.SharePoint.Library.SPRequestInternalClass.PutFile(String bstrUrl, String bstrWebRelativeUrl, Object varFile, PutFileOpt PutFileOpt, String bstrCreatedBy, String bstrModifiedBy, Int32 iCreatedByID, Int32 iModifiedByID, Object varTimeCreated, Object varTimeLastModified, Object varProperties, String bstrCheckinComment, UInt32& pdwVirusCheckStatus, String& pVirusCheckMessage) at Microsoft.SharePoint.Library.SPRequest.PutFile(String bstrUrl, String bstrWebRelativeUrl, Object varFile, PutFileOpt PutFileOpt, String bstrCreatedBy, String bstrModifiedBy, Int32 iCreatedByID, Int32 iModifiedByID, Object varTimeCreated, Object varTimeLastModified, Object varProperties, String bstrCheckinComment, UInt32& pdwVirusCheckStatus, String& pVirusCheckMessage) --- End of inner exception stack trace --- at Microsoft.SharePoint.Library.SPRequest.PutFile(String bstrUrl, String bstrWebRelativeUrl, Object varFile, PutFileOpt PutFileOpt, String bstrCreatedBy, String bstrModifiedBy, Int32 iCreatedByID, Int32 iModifiedByID, Object varTimeCreated, Object varTimeLastModified, Object varProperties, String bstrCheckinComment, UInt32& pdwVirusCheckStatus, String& pVirusCheckMessage) at Microsoft.SharePoint.SPFileCollection.AddInternal(String urlOfFile, Object file, PutFileOpt fileOpt, String createdBy, String modifiedBy, Int32 createdByID, Int32 modifiedByID, DateTime timeCreated, DateTime timeLastModified, Object varProperties, String checkInComment, SPVirusCheckStatus& virusCheckStatus, String& virusCheckMessage) at Microsoft.SharePoint.SPFileCollection.Add(String urlOfFile, Byte[] file, Boolean overwrite, String checkInComment, Boolean checkRequiredFields, SPVirusCheckStatus& virusCheckStatus, String& virusCheckMessage) at Microsoft.SharePoint.SPFileCollection.Add(String urlOfFile, Byte[] file, Boolean overwrite, String checkInComment, Boolean checkRequiredFields) atMicrosoft.SharePoint.SPFileCollection.Add(String urlOfFile, Byte[] file, Boolean overwrite) at Labinal.IMS.Library.Parameters.Extensions.CopyToList(SPFile theFile, SPList destinationList, String relativeDestinationUrl, String fileName, Boolean overwrite, Int32 previouslyPublishedFrontOfficeItemId) at Labinal.IMS.Library.Helpers.DocumentTools.<>c__DisplayClass1.b__0()

SPFileCollection.Add Method

            copiedFile = filesInDestinationFolder.Add(fileName, binFile,true);

tried using all overloaded methods but still does not work.