I've been using iTerm as a popup "visor" in Mac for many years now. It seems like once every three or four releases, something happens to Mac window management that breaks it, and that's happened this year.
When the Profiles / Window Space option is set to "All Spaces," hitting the popup hotkey shunts the user over the the Space where the window was first made (I believe that's the "Current Space" behavior), instead of popping up in any — or more specifically, the current — space (the "All Spaces" behavior).
Hope this isn't a tough fix. Thank you for your hard work and an indispensable tool.