Based on the screenshots you provided, I concur that it appears SAM is not properly reporting the status of your Dell power supply. Please verify WMI reports the proper Power Supply Status using WMI Explorer by looking at the Root\CIMv2\Dell name space, querying "CIM_PowerSupply" as shown below.
If WMI is properly reporting the correct status of the PowerSupply but SAM is not, please open a case with support and reference this thread. It may be that you've found a bug.