I've only sporadically been able to see the flicker, I can't reproduce it reliably, but I think I've seen it happen.
So you knew the bug is there. This issue is there already for around 8 months. I believe it wasn't reported earlier because C2 community is very small and not many people update NW.js to the newest version each time it comes out. Also not many people actually make desktop games (mobile dev are majority I guess) and over that, it doesn't happen on every machine. And of course, most people don't care/bother to make a report.
So because C2 community is small it looks like it doesn't happen that often. But it does happen. And now imagine that someone makes a successful game which gets thousands of downloads on Steam. Customer review section would turn red for sure. So I just wanted to highlight that for whatever reason it is, your product is not able to provide a well working desktop app at the moment with the latest NW.js version (I mean the one which is able do be downloaded from Scirra's site). And until this is fixed by whatever party I suggest to announce NW.js 0.13.2 as recommended version for Construct 2 - just in case someone makes a great game and bring a huge sh*t storm on C2. So that's just my suggestion. Of course you will do whatever you find right.
It seems to only happen in fullscreen mode in NW.js, not in windowed mode, and not in fullscreen mode in Chrome. Can you confirm this is the case for you too?
Yes. We already mentioned that few times on the post related to this issue. It only happens in fullscreen mode in NW.js 0.14.x and up.
If it's specific to NW.js there's not a lot I can do - I'd recommend reporting it directly to NW.js. One tip though: tests are better when they don't need user input, just replace the mouse click event with every 0.05 seconds or something like that.
I've edited the bug report (first post here) and added automated capx.
This capx has only two events:
Another thing I noticed is the dependence between the sound trigger interval and the sound's duration. The sound in the capx is 0.253s long. If we loop it to be triggered with 0.3s or higher interval then the flickering issue occurs.
However if we set Every X second condition to 0.1s for instance then the flickering does not occur. Also when we simply trigger this sound as looped, the flickering does not occur.
I don't know what's inside the Audio plugin, but I'm guessing that there's a - let's call it - "silence" trigger after the particular sound stops playing. It must be something common of Audio->stop(tag) function and when the sound has ended.
So it's not Audio->play(tag) which causing this flickering, but the end/stop of playing the sound.