Category always defaults to first category made (1)

Description

Installed 4.7.0 beta on a system running FreeBSD with PHP 4.3.11 and MySQL 4.1.9.

Running aggregator module:

1) Added new category (1).
2) Added new feed (1) to category 1.
3) Added new category (2).
4) Added new feed (2) to category 2.
5) Checked and feed (2) is categorised under category 1
6) Edited feed and changed to category 2.
7) Checked again and feed (2) is still categorised under category 1
8) Checked MySQL tables and both feeds are indeed categorised under category 1 so this is not a page caching issue.