Import with update erases phone numbers

Importing data records with update causes phone numbers of one type (eg mobile) to overwrite phone numbers of another type (eg phone).

This problem was discovered on a live v1.4 system and has been verified in the v1.5 demo system.

Detailed Steps:

1) Create a file like the one attached, which just has 3 columns (First Name, Last Name, Phone Number), and only one row of data. For ease of this test, pick a First Name + Last Name combination that does not exist in your current contact list.

2) Make sure duplicate checking is set to First Name, Last Name.

3) Import this single record file. (I used "Update", but that should be insignificant for THIS step.)
Map First Name to First Name, Last Name to Last Name and Phone Number to Phone - Home - Phone.
Complete the import.

4) Verify that the Phone Home Phone is set to the phone number that was imported, and
no other phone numbers exist for the imported contact.

5) Import this same single record file again. Set the import type to Update, but this time
Map First Name to First Name, Last Name to Last Name and Phone Number to Phone - Home - MOBILE.
Complete the import.

6) Examine this contact record. Note that Phone-Home-Mobile is now defined and
the Phone-Home-Phone number has been erased.

This bug prevents updating existing records when the goal is to update multiple phone numbers.

Note that modifying the file to have two phone number columns does not solve the problem.
Even though both column are mapped to separate phone number types (eg Phone and Mobile),
only one of the two numbers is ultimately imported. If there was a phone number of the alternate
type already in the database, it is erased, as well as not being imported.

NOTE: Even switching from Update to Fill does not solve this problem.