Saccades Krups Dolce Gusto Infinissima (KP173B10)

Hello to all of you,

Yesterday, I bought a Krups Dolce Gusto Infinissima KP173B10
, I followed the first cleaning procedure and the machine is directly connected to a wall socket (no extension cord...)

I used the capsules offered in the "package" and I also bought some cappuccino (Nescafé Dolce Gusto)






.
The problem I have: whatever the capsule, the motor (pump?) jerks... These are micro-cuts in the famous "rrrrrrrrr" characteristic of this kind of machines. It does not prevent the coffee from flowing, but I wonder if it is normal (micro-cuts to regulate the pressure?...) or if it is a defect that would require a return in warranty...
If needed, I can make a short video with sound to clarify the problem.

I thank you in advance for your advice, and wish you a nice Sunday (even if it's raining at home...)