First the processor is designed to never go beyond it engineered safe voltage levels unless you manually Overclocked the processor or manually changed the voltages yourself. So I wouldn't worry about it unless you Overclocked or messed with the processor's voltage parameters.
PBO is Overclocking but within the Processor's designed engineered safety limits. But it will still void your Warranty but it is safer than manually overclocking in which you might damage the processor with a bad overclocking.
The processor can have some high instant spikes but it is a very short time and within its safety limits and normal. But if the Processor is running at 1.5 and above all the time then you need to troubleshoot.
If Ryzen Master is showing everything fine and there are no Yellow or Red icons then you are okay. Remember that even though your computer is at idle, you may have several background programs running which might cause what you are observing.
