threemiles, this is an interesting image! If true, the vertical variations can be consistent with plane's (designed) self-trim on descent at a low engine speed (i.e. unable to maintain level flight) with no moves on the respective control surfaces (elevator and pitch trim).
Question: It is possible for the A320 to descend on heading hold, wings level and autothrust disengaged?
http://www.pprune.org/rumours-news/5...ml#post8914431