Video stalls

I have always downloaded rides and don’t display maps of my ride in order to minimize (eliminate?) the need for any server interactions. Today while riding a 4k-resolution video of the Glaubenbergpass using the latest version of FG on windows 11, I noticed an interesting issue - any time that my speed was greater than ~1.4x that of the video, the video would stall. It would recover after a period which seemed to be related (in some way) with the amount of time that I was at a speed greater than 1.4x the video. I could trigger the video stall whether going uphill or downhill. If I stayed below 1.4x, I had no problems. Given that the ride was isolated to my computer, this seems odd. Does it indicate some type of buffer issue ?