Active sense messages are weird.
If a transmitting device using active sense doesn’t send any other MIDI data for 0.3 seconds, it sends an active sense message to say “I’m still working OK”. That seems harmless enough, but…
If a receiving device that handles active sense messages receives one, it assumes there will be more coming from the same source, and if it doesn’t receive another message in the expected time frame it terminates any notes previously sent that are still playing, assuming the device has been switched off so it will never get proper “note off” messages to end them!
That might account for your random missing notes, if the timing is going wrong somehow.
Usually the best thing to do with active sense is disable it. There should be a setting on your keyboard do to that.