Do you have “Show in Timeline” on for the Smart plugs?
You’ll also see in there that if you attempt to run more that 3 fully-propagated HS300s you will likely run into some problems. At 10, you certainly will! Sense processing starts to max-out at around 20 smart plugs. Each of the plugs on an HS300 is counted as “a smart plug” so one HS300 counts as 6 plugs.