hope we'll manage to nail it down somehow
I like troubleshooting odd ball problems. I am almost as curious as you are now.
With APE2 off, boot up and delete the previous ThrottleStop.INI configuration file before running ThrottleStop. Deleting the config file allows ThrottleStop to read the turbo power limits that the BIOS has set. Is PL1 set to the Intel recommended 65W default value when APE2 is off?
The log file you posted showed that the CPU was using the 47 multiplier when it was fully loaded just like it is supposed to be using when 8 cores are active. Power consumption reached 151W with zero throttling. The VMAX throttling only happens when the CPU load is reduced. At full load and 4700 MHz the VID voltage shows 1.3135V which is fine. When the load is reduced the VID voltage shoots up towards 1.5000 V, That is what triggers VMAX throttling.
That is why I recommended playing with the loadline settings. Reducing the loadline values can help tighten up the CPU voltage so there is less voltage difference between light load and full load. Clearing the V-Max Stress box in the ThrottleStop FIVR window tells the CPU to ignore any throttling when the CPU detects that the VID voltage is high.
I just had a look at the log I posted. The VID was also sky high when running the Cinebench single core test. 1.5427. Yikes!!
The loadline mod I did shows that the actual voltage going to the CPU is far less than 1.54V. I have no worries. Actual voltage is probably somewhere around 1.35V. I will go start another single core Cinebench run to see what HWiNFO reports for actual VCore voltage. I told you I was curious! Makes one wonder how many other people have this same problem during single core testing that you have.
Edit - When running my CPU at a steady 5000 MHz, actual CPU voltage was 1.323V to 1.332V during Cinebench single core.
With the 10850K set to its default turbo multipliers, it will use the 52 multiplier when 1 or 2 cores are active which is the same as what your 11900F is supposed to be using. The highest multiplier I saw was 51.93. The VCore voltage went up to 1.439V so basically this CPU needs an extra +0.1V to run 200 MHz faster.
A CPU that required lots of voltage to run stable at high MHz was not good enough to be called a 10900K. Intel lowered the maximum clock by 100 MHz and sold these rejects as 10850K. This is a fairly low voltage chip up until 5000 MHz but after that, the voltage table goes up rapidly.