About 30 minutes ago I downloaded the newest version of AHK (v1.1.22.02) and I believe I've found a bug (and yes, I have tried restarting my computer).
Whenever I use ImageSearch with Google Chrome open, the image is never found. However, the second I close Chrome, ImageSearch functions normally again.
I've been able to reproduce this while Chrome is minimized, windowed or maximized.
Chrome may not be the only program that causes this error, but it is the only one I've found at the moment.