To troubleshoot this problem, reboot and run HWiNFO. Do not run ThrottleStop.
Have a look at what speed the RIng/LLC is running at.
I prefer to use the Windows High Performance power plan when testing so the CPU and Ring are both running at full speed even when idle. Now start ThrottleStop and watch to see if the cache speed changes. Perhaps ThrottleStop is changing the cache speed or perhaps ThrottleStop just accessing this register in the CPU is enough to trigger yellow EDP boxes in Limit Reasons.
You can also use HWiNFO to watch the Limit Reasons flags both before and after your start ThrottleStop.
EDP OTHER throttling is not well documented by Intel. There are a variety of different things that can trigger this type of throttling. The important thing is to watch what speed your cache runs at. If it seems to be running at full speed then I would not worry too much about EDP lighting up once in a while.
I do not own a 11900K for testing and development purposes. If ThrottleStop is doing something funny and is triggering EDP throttling, there is probably no way that I am going to be able to diagnose and solve this problem. My similar 10850K does not have any EDP throttling issues. If you set a negative offset voltage in the BIOS, you do not need to check the Unlock Adjustable Voltage box in ThrottleStop.
When you check the Speed Shift box in the TPL window, you can set the Speed Shift Min and Speed Shift Max values to whatever you like. You can set Speed Shift Max to 255 so it does not interfere with your maximum CPU speed or you can lower this value if you want to slow your CPU speed down.
I leave Speed Shift EPP on the main screen unchecked. Use the Windows High Performance power plan if you want your CPU to run at full speed when it is lightly loaded. Windows will automatically set EPP to 0 when using this plan. If you switch to the Windows Balanced power plan, Windows usually sets EPP to a value of 84. If the C states are enabled, it is OK to run your CPU at full speed all of the time. The C states drop unused cores down to 0 MHz and 0 volts so there is no need to slow the rest of the CPU down.