UPDATE - with patch 4.12.0, this officially made it onto the Known Issues list. So progress!
[Side note: this has been going on for a long time, so I don’t want to imply that it just recently started]
For some time now, during the prologue mission Dark Whispers, near the start of the mission, there’s a shuddering effect that happens 95% of the time on both my desktop and laptop.
Specifically, it starts around the time that the first Zerg attack wave prepares to move out:
- Mission starts
- Talis speaks
- Zeratul speaks
- The Zerg attack path graphic is shown on the minimap
- Zealot and Zeratul speak
Then at about 1:57
- The boss icon and path appear on the minimap - shuddering can sometimes start here
- Zeratul speaks - shuddering usually starts while he’s talking
- Kerrigan speaks - shuddering can sometimes start here
The shuddering will stop when the Zerg wave physically moves out, which is never at the same time.
Sometime it shudders just a few times, sometimes it shudders for several minutes, and everywhere in between. What seems to be a factor is the longer the shuddering occurs, the more delayed the attack wave is. So for example if the shuddering is 4 mins, the wave is delayed 4ish mins. That can sometimes cause the second wave to move out before the first one even finishes attacking the Mobius base.
Here’s a video of it. I’m not sure why it uploaded so quiet. You’ll have to turn your volume up to hear it.
EDIT: Just to add to the video: notice at the end, because the first wave took so long to move out, the second wave prepares before the first wave even begins to attack the Mobius base.