Err-There are multiple records in this file which resolve to the same target record in the database

we have been using 19-tab for initial customer upload and 4 tab to update Bill-to site, Additional Address elements and Reference Accounts (with references used in 19 tab).

Error received "There are multiple records in this file which resolve to the same target record in the database. The last of these records will be processed for import."

Upon checking there are no actual errors like duplicate OSR’s or address lines duplicate (though we have same address lines (already existing in the instance through 19 tab upload-Eg: Address line 1 ) differentiated by Site purpose within a customer).

Eg:

When tried to extract the errored records and upload them, again partial set of records gets updated and remaining are errored out