Recording artifacts, 50 samples jump

I’m using Audacity 2.0.0 on Ubuntu 12.04 (distribution version).
Recording was done with an usb audio codec, I think TI Burr-Brown PCM2900.

From time to time (random) I get these artifacts:

Anyone ever noticed these artifacts or know how to change configuration to get rid of them?

Important to mention is that I don’t hear the artifacts while recording.
The PCM2900 is inside a Xone:42 audio mixer.

Skips and jumps are a pain to trouble shoot. There are so many different things that can cause the problem.
There are some issues to look at here - some are specific to Windows, but others apply to any computer:

What settings are you using in the device toolbar?

I use ALSA USB Audio Codec.
I now am trying to go way back in time with Lucid and Audacity 1.3.12.
The machine I am trying it on is an Asus Zenbook Prime UX31A.
As far as I can see the artifact are gone, cross fingers!