exactly same problem here...
libreelec community build (LibreELEC-S912.arm-8.2-220.127.116.11) video stuttering when subtitles are shown but livetv (mediaportal tvserver) running without any problems.
builds from wrxtasy (LibreELEC-S912.arm-8.2.4-Subtitles-ff, LibreELEC-S912.arm-18.104.22.168.force.444.10bit, LibreELEC-S912.arm-22.214.171.124-fix-lost-audio-v2) videos with subtitles are running smoothly but kodi crashes everytime i'm starting livetv or even when I try to watch a recording
please wrxtasy can you have a look on this? If you need something like logs or so just let me know!
Yep, I also get crashes with watching live TV via the MediaPortal PVR plugin using LibreELEC-S912.arm-126.96.36.199.force.444.10bit.