I thought it might be interesting to share the following:-
I’ve posted various moans over the last 18 months or so with RPi failing to replay videos from a NAS attached via ethernet and fstab NFS. This config was the end of a (long) journey starting with RPi 2 and KODI NFS connection, and working my way through several versions of RPi hardware (up to 3B+), SD cards, network switches, NAS devices, network cabling, power supplies, versions of XBMC & KODI, OpenELEC/OSMC/LibreElec, buffer configurations… all to no avail. A fairly exhaustive sample I’m sure you’d agree?
…and prior to my problems starting (back in RPi 1B days) my simple SMB connection to the NAS used to play fine (otherwise I’d have given up many months ago)…
Switching from RPi hardware to Vero 4K solved the problem completely. No unexplainable replay glitches for months. Everything else is the same (including the fstab NFS config on the Vero).
I conclude that there is something fundamentally iffy about ethernet on the RPi (either hardware or kernal), and have moved on to enjoying my movie collection via a better hardware platform. YMMV.