[Milhouse]

EDIT:
I have improved my nfs export definitions, which should eliminate any possible problems there. this is a much better/simpler approach than the guide on the wiki or the ubuntu wiki. Details here: https://gist.github.com/miigotu/c7df712997cd8745bd7a

crossmnt and nohide on the top /export are especially important, fsid=0 important for NFSv4.

You need to explain if you're using OS mounts in OpenELEC, or libnfs nfs:// mounts in Kodi (on OpenELEC).

libnfs doesn't support NFSv4, and will connect using NFSv3.

I'm not even sure if OpenELEC supports NFSv4 "natively", as an OS mount, and you may need to use mount.nfs4 installed from Unofficial (see: PR67), so you could be wasting your time (or simply causing yourself more grief) by trying to use NFSv4 exports - just stick with NFSv3, as this works no problem...

Edit: Reviewing your previous posts from April when you first reported the play-next issue, you were using nfs:// at the time, which is libnfs and doesn't support NFSv4... Mind you, it's the same libnfs in both Chimney and test builds, so wouldn't explain any performance difference.