Why is the centre C note of the 61 Key keyboard not 'Middle C'?

[Newcleus]

I'm following an online keyboard/piano course and they often need me to play at 'Middle C' of the (piano) keyboard.  I have to drop an octave with the button to get it centre of the keylab's layout.  Not a showstopper but an annoyance all the same... 

IIRC, there is a 3 octave drop/rise either side but why isn't a piano's center C at the center of this keyboard by default?  Is this a typical thing with synths?

[LBH]

I don't have a Arturia controller.

But keep in mind, that it's a controller and not a synth. A controller output midi notes.
Middle C is midi note 60. In Hertz middle C is 261.625565 hz in a A=440 hz tuning.
In different software middle C can be labeled C3-C5, depending on the software.

What you can do is to check on which note your controller send out midi note 60.
The software you use should then send out a 261.625565 hz C note, if the software is correctly tuned to midi note 60.

On my Novation 61 key controller midi note 60 is the C that start the third octave (the third C note) - so there is two octaves below and 3 octaves above this note. In your case it would be the nearest C left of the middle of the controller. If i understand you correct, then you perhaps think middle C is the one to the right of the middle of the controller.
On a standard real piano middle C also is left to the center.

[Lince Pálido]

I think it could be related to Yamaha or Roland compatibility.

I think one brand used C3 and the other brand used C4, but I can't remember which one.