Screen share flickering

Using Desktop client on Win10. Friends will stream their game to me but when I view it the video flickers back and forth on a frame-by-frame basis. Basically, if we consider the FPS to be 30 and the stream to be matching this both in recording and in presentation, instead of going through the frames 1, 2, 3, etc, the screen will flicker ahead and back 1, 3, 2, 5, 4, 7, 6, etc.

System is fairly high-powered, AMD Ryzen 3700x, RTX2070, 32GB DDR4. 

Video of a screen share in which this happens (be sure to view in HD):
https://drive.google.com/file/d/1PIgKUlssd5StAevnygyHe0U5xua66kOb/view?usp=sharing

I've had them try different streaming options several times. Some days it works fine, others it doesn't. I have no idea if there's even a particular setting that causes this.