I can't confirm if the new update has fixed the Ithaqua locked-investigator bug, but it seems to have introduced a new one. On "Horrible Visions", I had a terror and peril, but it would not allow either into the appropriate task. The other task had a peril, so I tried sliding the peril there, and it did enter, but then I could go no further…the X did not appear to allow me to cancel, I couldn't solve either task, and essentially I was "trapped" and the game effectively ended there.
This seems to be related to some other "exploit" bug that the update claimed to fix (not the locked-investigator one). Now, I only just downloaded the update and tried it, and this happened within the first few tasks, so I don't know how often it will recur. But if it happens often, as it seems it may, and others also confirm this bug, well. Disappointing to say the least.