@drjb Turning a plug off would not affect if they are or are not appearing in Sense. It would literally just be controlling whatever is plugged.
@demiller9, aside from toggling the NDI setting in Sense as Kevin suggested, have you tried power cycling the KP115’s and/or the Sense itself?
The Sense team can correct me, but I think generally speaking, Sense isn’t doing much special in regards to the kind of TP link device it is talking to. I believe all of the plugs speak “the same language”. So all Sense is doing is saying “hey, any TP link plugs out there, if so, tell us your name and how much power you are using right now” and then it just listens for whoever replies. I don’t necessarily believe that Sense is going "ok, this is data from a HS300, so I have to do X with it and this is data from a KP115, so I have to do Y with it. I think all the plugs basically reply the same way.
I mention this as the fact that it was only KP115’s that dropped of may be a red herring that its a Sense issue and may be related to a KP115 issue. Since the Kasa website still seems to list these as “coming soon”, I can’t find any support info, but any chance that there was a firmware update for those plugs?
I know back in November, TP Link started changing their firmware to block the local access that Sense and other systems rely on, so I’m wondering if the same happend here. While I would expect if this were the case we would see more reports from other users, its possible its a slow roll out.