@ Cat: Yes, if you have Hyper-Threading enabled, you are using 24 cores and your CPU is affected.
If HT is disabled, you don’t need to worry.
The engine.properties file is not going to affect VEP in any way, as it only relates to the Cubase Audio Engine.
I don’t know how VEP works internally, but it will access its own 32 threads to my understanding.
@silhouette: If you are using Windows 8.1, the issue is somewhere else, this limitation is not present in Windows 7, 8 and 8.1, only in Win 10.
As Rommelaar wrote, the limit applies to Logical cores, which includes physical and HT.