Strange behaviour front brake lever R1200Rt 2013

[Stigwh]

Hi,
on my 2013 RT there is sometimes a strange "feel" to the front brake lever. When I pull the lever, it moves smoothly but will in some case give a tiny weeny response or feedback in the lever as if it "kicks back" about half the way in. The brakes works as they should, and it only does not happen if the brake has been applied continuously - as in short time (10-20 sec) between each pull. The brake fluid has just been changed (by dealer). Bike has only 17000 kms on  it, so I guess nothing has been worn out.
My main concern is if this may be related to a possible bad ABS-unit. Secondary if this could be linked to air trapped somewhere in the system. I cannot feel anything from rear brake pedal (but then again - I@ve got boots instead of gloves as contact points :-) )

I can probably live with it, but I have never felt this before on any bikes. My friend has the same bike without this issue.
The bike is new to me, hence I have no idea if it has always been like this.