Kodi displays a percentage indicator on-screen when playback stalls and the 'stream' needs to be buffered again. There's a multitude of reasons for a stream to stall and never recover, but the main candidates are a bug or something in the hardware decoder, or something in the media that ffmpeg doesn't handle right.
Things to try:
a) Disable DRMPRIME and hardware decoding. If the media now plays (software decoded) the issue is in the hardware decoder.
b) If not 'A' the enable things again and update to a current LE12 nightly since this has newer everything
c) If not resolved with 'B' share a reasonable snippet of media so that Pi engineers can have a look.
And if posting again, share a debug log that demonstrates the issue.