Once more, since this is going away, there's little reason to report it, but I GS'd simply to make the run back from the Tser Pool, and it seemed to have no effect at all. Every hostile creature along the way--even bandits--gave pursuit and attacked. Moreover, when Iridni started fighting back, the GS indicator didn't go away. (Have screenshots of all of this.)
She was not under the effect of any other spells, although she was suffering slight exhaustion.
GS finally was broken (the "trying to affect" message issued and the glowy effect and icon in the top right went away) when she healed herself.