Necro posting on this because I was searching for something and stumbled on this thread and I didn't see an answer.
The horizontal lines appear to be z-bearing binding. This is a common problem on the UM2. The solution is annoying. You need to buy higher quality z bearings, tear the machine down, and rebuild it.
I had the same problem with my UM2. It's solved now, but it was a pain to solve. I don't know how Ultimaker let crappy z bearings like this out the door. It's a manufacturing defect.