import of contacts fails (but doesn't say so) when a relationship is specified using email address that exists twice

Importing Organization contacts with a field for related contact info using 'Employee of' matching on 'Email' fails if there are two email addresses in the database that match the imported field. The final import step however returns a screen indicating successful import.

To create on the database:
1. Add two Individual contact records in the database with identical primary email addresses (me@test.org).
2. Create a CSV file with multiple new Organization record to import, and add a column with header 'Employee of'. In the first row set the 'Employee of' value to the duplicate email address (me@test.org), and set all other values to valid email addresses of Individuals in the database.
3. Import step 1: upload the Organization CSV file
4. Import step 2: for the 'Employee of' field specify a match to 'Employee of', 'Email', and also select Add new contact to group.
5. Import step 3: select a group to add the imported records to. (Test Group)
6. Import step 4: the summary table indicates successful import of all records, and does not include a row reporting on the group addition. What has actually happened is that the CSV file parsing stopped after the Organization record that had an email with two matches in the database. No records were added to the group (Test Group).

Although there should not normally be two records in the database with duplicate email addresses, this import step should be robust enough to handle that case. Desired behaviour is probably to skip records that have duplicate relationship email matches and include them with in skipped message lists with error message.