grey screen when stepping through video

[radar]

My video plays fine until I start jumping around the video by either clicking the step forward/backward buttons or clicking to another place on the time line. This happens on most but not all of the videos I'm playing (these videos are typically, but not always, recordings of webinars made using the GoToWebinar recorder). I've tried many other solutions (which do not solve my issue) put forth for grey and pixelated playback, although my normal playback is just fine. I only get the problem when I start jumping around the video.

I'm running VLC ver 2.2.6 on a Windows 10 PC with: i7-8700, 32GB RAM, Asus Maximus X Hero motherboard

thanks