This only started happening once I installed the latest update.
I create a instrument track and record some midi on it.
On playback the midi out activity monitor on the transport window looks like a metronome count as it flashes on an off repeatedly.
I stop playback and the midi out activity flashing does not stop until about 15 seconds later.
Is this normal?
Hi,
Make sure, you are not using any Remote Device in the Studio Setup. Some of them need (or send) a signal like “I’m still alive”. 
Thank you for such a quick reply Martin.
I did what you suggested.
Here is the strange thing about it.
I went into studio set up.
Checked that there was no device transmitting midi.
The only device selected for midi out was my Native Kontrol S88. ( Komplete Kontrol DAW-1 )
All quick controls showed an “R” only.
I selected “not connected” on the “midi out” on the Komplete Kontrol Device set up and the problem stopped.
I then saved the project, closed it and, then reopened it.
I had to then go into studio set up and do the same thing as outlined above as it will not save my previous settings.
I did click “apply”
Even after I select 'not connected" all the komplete kontrol synths I had loaded still played.
However when I create a new Komplete Kontrol instrument track the studio set up reverts to midi in and midi out both showing
Komplete Kontrol - DAW-1.
As a side note as I’ve posted in another thread about Cubase crashing when you select “remove empty track” when an Native Instrument track is loaded on it.
That’s not happening in this test project i created.
It does still happen when I open the project where the crashing first started even though I go into studio set up and change the midi out to not connected.
You can use any Remote Device without constant Midi Out activity 
Just be sure there is no device selected in the Midi-Output section!
Cheers!