What specifically is the pattern you’re seeing run ~300 times per day? The spike to around 100 W with a dip in the middle, or does the waveform in the screenshot show two spikes? i.e. is the image showing one run instance or two? Do you consider the small ripple of power usage after these ~100 W spikes to be part of the cycle? How long is it typically “on” for? Can you show a larger time period to get an idea of how it cycles and how consistent it is across cycles? Is the time between cycles constant?
300 runs per 24hr day is about 12.5 runs per hour, or once every 5 minutes. No initial spike suggest there’s no electric motor component involved here (although motors can have no initial spike). For resistive heating elements, the power tends to decrease throughout the cycle as the resistance of the element increases (particularly for the initial heating cycle when the temperature is increasing). It’s hard to say for sure with a relatively short cycle. If it’s resistive it’s likely an intermittent cycle you’re seeing to maintain a certain temperature. My Keurig personally looks more similar to the ‘standby’ example below (both in cycle frequency and the ~250 W usage), but this may differ between Keurig models or brands of instant coffee makers. Could also be other small heating devices like an aquarium heater. I’d also consider laptops or computers. I believe I’ve noticed cyclic pulses to maintain a full battery charge.
Primary Keurig Heater vs Standby Keurig Heater
This hot water recirculation pump example seems interesting. Not the same wattage as your spikes but could be a contender if you’re seeing intermittent sets of cycles, rather than consistent cycles over 24hrs.
I’d recommend getting yourself one smart plug like the Kasa HS110 or KP115 to help troubleshoot with.