I’ve started to experience a massive problem when trying to play my level in the editor viewport.
I will provide a video of whats happening at the end of this post.
Some quick info:
I have not changed anything within Unreal since the last time it worked flawlessly.
I’m not having performance issues, at the time of recording the video of the problem my CPU (i7 7700K OC to 5GHz) was about 60% util, GPU (ASUS ROG STRIX 1080Ti OC) at around 45% util and RAM (24GB) at around 40% util.
The only thing that did occur before this started was an update to the GPU driver. HOWEVER, I played the level with no problems ONCE after the update, but the second time I played it the problem started. After the problem occured I have tried restarting the PC, re-installing my graphicsdriver but to no avail. What do? 
Here’s a video of what’s happening:
Video