Did you at one point have 6 CPUs and then reduce the number to 3?
This may not scale for you, but you could validate the polled information with any traps that you can get sent. Could show you which polling to believe.
In this case i would believe Prime and the CLI for actual data on the cores. However your 3850 may have 1 CPU with 4 cores and Prime and the CLI are reading data for each individual core. Solarwinds usually uses a higher tree MIB that reports the utilization of the CPU as a whole, not the cores.
From the screenshot of your Solarwinds charts, I would say something is not right with the way solarwinds is recognizing the device as you are showing different types of cpus in the chart, the cpus names do not match and are not complete. You can perform a MIB walk and probably find the OID which has a table of the utilization by core for the CPUs and then create a custom poller to collect that data and present in the custom poller chart to track the indivudal cores. but if i was you I would try a rediscovery followed by examing the resources (list resources) to make sure there is no legacy or orphaned resources attached to that node in Solarwinds.
Cisco has a doc on 3850 with high CPU--- Catalyst 3850 Series Switch High CPU Usage Troubleshoot - Cisco