cores allocation not use all cores after change

[baudav]

Hi,
If change cores allocation when mediacoder run; it's not possible with mediacoder to use all cores:
If tick All Cores: no change (if 4cores not used, if tick all cores: 4 cores stay not used)
If untick one core, and tick each core, one core is never used!
screenshot
And must change affinity by taskmanager to use all cores.