Zarro

Hi guys, A couple of weeks ago I bought Ultimaker 2 - Yaaay merry xmass 2 me ! This week I had more time to play with it and to print some 3d models. I noticed recurring printing pattern that does not look okay or normal to me. I am complete nub in 3D printing even don't know how to categorize it. Thought underextrusion? Will be very happy if you help me solve the problem. It happen every time at the same height of the model. Please have a look at the pic. Thanks a bunch in advance ! Zarro Models are printed with PLA material i got with the Ultimaker 2 on factory settings for PLA; the plate is realigned/set before each print task.