Sense definitely has a bug in how it communicates to the Wemo and TP-link smart plugs. I have not contacted support about it, though I did start thread about this last month: Smart plug power data glitches
My reasons for calling this a Sense bug is that, just as @ian.heritage states above, that there are periods of time when Sense reports 0W from a smart plug when the smart plug apps (Wemo app or Kasa app) are able to successfully communicate with the smart plugs. While the LAN that Sense and the smart plugs are on may experience issues that cause 1 or 2 seconds of smart plug data to be missed, Sense should not loss contact with the smart plugs for hours.