Have this problem too on 2 machines and has NOTHING to do with SD cards.
It's a libreelec problem and guys of libreelec... stop pointing fingers to hardware, adapters etc etc etc. That's bullshit and you know it!!!!
NEVER NEVER NEVER EVER had this problem with OSMC and even openelec a long time ago. NOT on my rpi2, rpi3 and rpi3b+
Just thought I give libreelec a (new) try in the new year and same f*cking problem on both machines.
So I'm going back to OSMC. And probably forever.