Hey Simmer,
This issue affects all of the Modifier keys (Shift, Cmd, Alt, FN, and Apple keys)
I was not able identify whether it was Parallels or the Logitech software is the cause of this issue. I had hoped that it was Parallels. (Logitech does not support Mac very thoroughly. great support for PC hardware.)
Unfortunately I never found a fix for this issue. I ended up buying a 2nd G13 on ebay for $20 and I run 2 of them side by side.
EDIT:
Also as a heads up there is a irritating as hell bug with the latest Logitech software for Macs that removes any instance of the "A" key in any multi-key macro. Every time you restart the Logitech software you have to go and re-add the "A".
Last edited: Mar 24, 2014