I'm not sure at which version this began happening, but I don't remember having this problem with 11.6.
It happens at least with 1.7.0 and 1.7.1 - I can't cross check with older versions right now, I'm afraid.
When repeatedly triggering hotkey cues (like say, gunshots), the sound plays with a delay of up to about 0.5 - 1 seconds, and key presses can even pile up in the keyboard buffer. However, this only happens when there are still manual cues queued up in the cue list, and the cue panel frame is populated with the upcoming cues. If I place the play cursor at the END of the cue list, so the cue panel frame is empty and there's nothing left to redraw, hotkey cues suddenly fire more or less latency free. It seems that the redraw of the cue panels is causing some major congestion - one processor core goes to 100% load when it happens.
It doesn't seem to depend on the actual number of cues in the project, only on the fact that there ARE cues in the cue panel frame. It happens even when no other cues are playing. I don't have to trigger hotkey cues particularly fast to make it happen. In fact, pauses between keypresses that are closest to the window refresh delay seem to be worst.
I can pretty much rule out a resource or a hardware problem. This machine is a well maintained Core i7-3770, 16 Gig of RAM, a presonous firestudio interface. Windows 10 Pro.
(On a side note: Rendering of the UI is generally very slow, and there seem to be a lot of unnecessary full redraws of the main window - and each readraw takes about 1-2 seconds during which the UI becomes completely unresponsive. For example, when entering a hotkey label in Cue Properties, every single keypress in the text box triggers a full redraw. That means, typing in a 10-character-label takes about 10 seconds to finish. Opening the Editor Window takes at least 5, but sometimes up to 10 seconds and I have not yet found a corellation for that yet. Same goes for the options window. Switching from Cues to Production Properties in the Editor can lock up up to 20 seconds - but only once. These might be separate issues or related - I have no idea

I am running a show that requires precise firing of cues via hotkeys and cue control devices (rs232) ... and it doesn't have to be ultra-snappy, but unfortunately hangups of half a second and sound beginnining to cue up is pretty much a showstopper.
If there's anything I can do to help solve this problem, please let me know.