I came across this:
https://wiki.libreelec.tv/hardware/raspberry-pi
Quote
This means HEVC support on Raspberry Pi 4 and 400 hardware is excellent as these devices support native HEVC hardware decoding,..., but playback on older Pi 01/2/3 devices will be challenging as FFMpeg software decoding is no longer optimised for Pi hardware, and users can expect SD media support only, not HD (720p and 1080p) support as seen with older LibreELEC releases.
so could be that stream was of a encoding type which pi 3 is struggling with.
So for now I will stick to LE9 on pi3.