This bug is still around in webadmin. I don't have multipath rules to test the fix but I tested it in QoS rules and packet filter rules and duplicate numbers are still there.
Tested on IE8 and FF on windows 7.
FYI: The bug is really bad if tested with IE9 and colums are sorted even if the status is not set to disabled. Just a heads up since its not a supported browser[:D]
Screenshots attached.