Logic Pro X keeps sending C0 notes to midi out when record is armed on a audio track

Question

I have a annoying problem with Logic Pro X, which I bought a month ago. Here's al little scenario that describes the problem.
I disconnect my audio interface, so that Logic Pro has to rely on my MacBook Pro's internal audio. This way I exclude my RME-FF800 from being of any influence.
I start up the Midi Monitor tool, to analyse what comes out of Logic; MIDI-wise.
I start up Logic set up a small test project in Logic Pro X, that contains:1 audio track
There's little button on the audio track with a red-colored "R". This is the button to "arm" this track for recording audio.
I push the little "R" button, the R-character turns white, the button as a whole turns red. The button starts blinking.
From this moment on Logic starts sending MIDI messages ....... huh?  Every second or so ... a low C.
In my regular studio setup this means that I hear a low repeated note coming out of my piano, every time I record audio.  How annoying!!
By the way ... a Guitar/Bass track has the same problem. All the other track types (External midi, software instrument, drummer) don't have this problem.
Help is deeply appreciated, because it drives me crazy and if I can't fix this .... I think I have to return to my previous DAW-of-choice (Cubase 7.5).
Here's the Midi Monitor output.
20:46:01.241          To MIDI Monitor (midi monitor)          Note On          2          C0          127
20:46:02.008          To MIDI Monitor (midi monitor)          Note Off          2          C0          0
20:46:02.774          To MIDI Monitor (midi monitor)          Note On          2          C0          127
20:46:03.541          To MIDI Monitor (midi monitor)          Note Off          2          C0          0
20:46:04.308          To MIDI Monitor (midi monitor)          Note On          2          C0          127
20:46:05.075          To MIDI Monitor (midi monitor)          Note Off          2          C0          0
20:46:05.841          To MIDI Monitor (midi monitor)          Note On          2          C0          127
20:46:06.608          To MIDI Monitor (midi monitor)          Note Off          2          C0          0
20:46:07.374          To MIDI Monitor (midi monitor)          Note On          2          C0          127
20:46:08.140          To MIDI Monitor (midi monitor)          Note Off          2          C0          0
20:46:08.908          To MIDI Monitor (midi monitor)          Note On          2          C0          127
20:46:09.675          To MIDI Monitor (midi monitor)          Note Off          2          C0          0
20:46:10.441          To MIDI Monitor (midi monitor)          Note On          2          C0          127
20:46:11.208          To MIDI Monitor (midi monitor)          Note Off          2          C0          0
20:46:11.975          To MIDI Monitor (midi monitor)          Note On          2          C0          127
20:46:12.741          To MIDI Monitor (midi monitor)          Note Off          2          C0          0
20:46:13.507          To MIDI Monitor (midi monitor)          Note On          2          C0          127
20:46:14.274          To MIDI Monitor (midi monitor)          Note Off          2          C0          0
20:46:15.043          To MIDI Monitor (midi monitor)          Note On          2          C0          127
20:46:15.808          To MIDI Monitor (midi monitor)          Note Off          2          C0          0
20:46:16.574          To MIDI Monitor (midi monitor)          Note On          2          C0          127
20:46:17.341          To MIDI Monitor (midi monitor)          Note Off          2          C0          0
Logic Pro X = version 10.0.6
Mac Book Pro = late 2008.
  Model Name:          MacBook Pro
  Model Identifier:          MacBookPro5,1
  Processor Name:          Intel Core 2 Duo
  Processor Speed:          2,53 GHz
  Number of Processors:          1
  Total Number of Cores:          2
  L2 Cache:          6 MB
  Memory:          4 GB
  Bus Speed:          1,07 GHz
  Boot ROM Version:          MBP51.007E.B06
  SMC Version (system):          1.33f8
Mac OSX = 10.9.1
  System Version:          OS X 10.9.1 (13B42)
  Kernel Version:          Darwin 13.0.0
  Boot Volume:          Macintosh HD
  Boot Mode:          Normal
  Secure Virtual Memory:          Enabled

Answer 1

The note is likely being sent out because of a Control Surface you have installed or used.... be it a hardware keyboard, controller or even an ipad controller app... such as Logic Remote or TouchOSC for example... or even an iOS software synth app that is sending midi over wireless....
So.. first make sure you have force quit any iPad/iPhone Logic/midi related apps and not just closed them..
Then if that doesn't fix things.. delete Logic's CS preferences... and Logic's own user preferences too...as described here..
Delete the user preferences
You can resolve many issues by restoring Logic Pro X back to its original settings. This will not impact your media files. To reset your Logic Pro X user preference settings to their original state, do the following:
In the Finder, choose Go to Folder from the Go menu.
Type ~/Library/Preferences in the "Go to the folder" field.
Press the Go button.
Remove the com.apple.logic10.plist file from the Preferences folder. Note that if you have programmed any custom key commands, this will reset them to the defaults. You may wish to export your custom key command as a preset before performing this step. See the Logic Pro X User Manual for details on how to do this. If you are having trouble with a control surface in Logic Pro X, then you may also wish to delete the com.apple.logic.pro.cs file from the preferences folder.
If you have upgraded from an earlier version of Logic Pro, you should also remove~/Library/Preferences/Logic/com.apple.logic.pro.
Restart the computer.
Do not forget to Quit Logic before doing this and then restart the Mac after doing this....