You are in a very large group and, of the friends I know that have Sense, 100% have significant missing detections. In my case, after years, I only have 17 (not very reliable) detections out of 177 electrical devices. Sense engineering characterized my home as “electrically noisy”, due to a variable speed well pump. Sense was an interesting idea, but an extremely difficult one, and they totally missed concepts like modern variable speed (e.g. ramping) appliances in their basic architecture.
It might be an incomplete detection for a variety of reasons - the heating element cycle being different enough between each new transition, other on/off noise in your house, etc. Sense might do better over time as it sees more cycles.
Progressive detection might be at work - there are certain kinds of detection where the bubble doesn’t come on immediately and the data shows up later when Sense is much more sure about the transition. This happens frequently for slower ramp devices - how can Sense know immediately that it is an EV charging if the ramp takes 3 minutes to reach full current ?