Printer ignores G29 command.

Hello everyone!

For the last few weeks I've been working on a chinese prusa i3 kit someone gave me to make it awesome again!
I downloaded the latest and greatest Marlin firmware to get the printer working again. No problems there.

After making sure that the printer actually prints I decided to add an inductive probe for autoleveling. I used bilinear leveling on a 4 x 5 grid as the build plate of the printer is slightly bent.
(I decided not to replace the bed and add a cheap probe instead as I want the costs to be minimal. I'm giving the printer away anyways.)
There's only a slight problem: the bedlevel command does show up in the LCD smart controller and it does autolevel the bed.
But as soon as I start a print is does not compensate. Also, adding the G29 to the gcode makes the printer do nothing.

Also important to note: the hardware is not configured incorrectly: all endstops are working properly and it homes like a champ. The printer also posts the right data in the Arduino serial monitor, so also no problems there...
Here's the printer calibrating using the menu option:
[www.youtube.com]
Can anyone help me out?

Kind regards,

Nando van Steenwinkel