I think we may be on to something here.
I have just tried a friends Intel NUC5CPYH and it worked straight out of the box when testing the latest Milhouse build of LibreELEC on my setup at home. The same Aug 16th build on my system still stutters every few seconds playing back the same file over NFS like I was on the NUC5CPYH with the refresh set to adjust to 24p on start/stop.
So going with what is on this forum we have:
Intel Sandybridge i3 2120 with HD graphics 2000: Stuttering
Intel Ivybridge i7 3770s with HD graphics 4000: Stuttering
Intel Ivybridge i3 3217U with HD graphics 4000: Stuttering
Intel Braswell Celeron N3050 with HD graphics: Working
Intel Haswell i5 4250U with HD graphics 5000 : Working
Could it be something that has changed in the Intel driver since v6.0.3 of OpenELEC that is causing the stutter on older (but still capable) hardware?