If it was a jb leak and not a jb rom, that very well could be the reason for losing root. As a leak is something like taking an OTA.
If you installed the leak via Odin, that is definitely the reason for losing root. My advice here, if you can locate the stock Ics files, do an install and re root.
I could be wrong here, but being the jb leak and not official jb is why the files aren't being recognized.
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