Mac Desktop Client doesn't Growl Tracks with / in Song Title

I've spent the better part of the last 2 hours on this issue.

Per the subject, song titles with a forward slash in them do not get announced via Growl. Oddly, Album names with a / seem to have no problem.

I can only assume it's a libUnicorn problem because:

Manually executing the generated AppleScript displays the Growl notification appropriately, and all of the track info (title, album, artist, etc.) is gathered in the same manner. Additionally, the data is also exported (AppleScript::asUnicodeText) in the same manner.

Running this script in AppleScript Editor works flawlessly:

tell application "GrowlHelperApp"
register as application ¬
"Last.fm" all notifications {"Track Notification"} ¬
default notifications {"Track Notification"} ¬
icon of application "Last.fm.app"
notify with name ¬
"Track Notification" title «data utxt005200650067006100720064006C0065007300730020002F0020005700680065006E0020002F0020004D006F006D0065006E00740020002F0020004C0061007300740020004300680061006E006300650020002F002000520065007600690073006900740069006E00670020002F00200043006F006E007400720061007300740020002F002000440079006E0061006D006900740065002000420072006F00740068006500720020002F00200044006500740061006300680020002F00200047006F006F0064006200790065» as Unicode text ¬
description «data utxt0032003000300039002D00310032002D00310037003A00200042006C0069007000200046006500730074006900760061006C00200032003000300039002C0020005400680065002000420065006C006C00200048006F007500730065002C002000420072006F006F006B006C0079006E002C0020004E0059002C0020005500530041000A0041006C00620069006E006F002000470068006F007300740020004D006F006E006B00650079000A00320032003A00330038» as Unicode text ¬
application name "Last.fm"
end tell

A Growl notification appears on executing the above, though notably truncated. This should be the same exact data that the (src/extentions/growl)growlextension.cpp script generates. But obviously that's not the case, because in normal execution of the Last.fm client, the notification for this song never appears. No errors in Console.app either.

Lastly, the actual act of scrobbling this information works just fine. It seems to be completely localized to Growl. Yet it shouldn't be a problem with Growl itself.

But... why?