Has anyone noticed ICS lasts longer than "2 turns" as it says in the description? A round is 6 seconds and a turn is 60 seconds, yes? I stopped counting at 4 minutes, but clearly it's longer than I thought.

I cast it using NRD, not that it matters as far as I know.

I can't test it, as I don't have a current save as Wild Mage, nor do I have BGT installed, but ICS should last 60 seconds, assuming that you have the AI timing set to default (30), and that BGT hasn't altered the spell in a way that extends the duration. Are you sure the spell is still active, and it's not a case that the icon has 'stuck' -- that sometimes happens.

I was under the impression that Tutu and BGT use BG2 rules, is that not right? The BG2 manual states a turn is 60 seconds.

I was not aware that icons could become stuck. Assuming that is the case, how would I know? The game does not show me the roll+modifiers of wild surge, only the final result.

I haven't heard of AI Timing, but I assume then that the default setting cuts the normal rules in half if you say ICS should last 1 minute.

Regarding testing, am I wrong in assuming you're suggesting I casts hundreds of spells(with and without ICS) and logging the results; then making a conclusion?

Regarding this icon bug, does this affect just the portrait, or also the status list when viewing my stats with 'R'?

The AI timing is the frame rate, or updates per second used in the game, and it affects everything time-wise, that's why it's important to leave it on default. You will see it in the miscellaneous tab of BGConfig program.

Testing: I am suggesting nothing of the sort. I simply meant that you could clear all status effects from your character, and then cast ICS out of battle, to check it's timing without having other statuses interfering.

As I said, the icon 'bug' is not common, and I've only encountered it a handful of times. I really don't have the answer to your last question.