I noticed this in my 2005 Golf GTI 1.8t. I was wondering if this could cause weird rev spiking and shifting issues. It basically had no power steering fluid. I replaced the pressure switch and added fluid, and so far it seems to be fine.
But curious of how a power steering issue can affect the engines rpm’s and therefore shift points.
When the power steering fluid level is full, the engine has to labor in order to turn the pump that creates pressure. When the fluid level is empty, the engine does not have to labor as hard. Air is easier to move than fluid. I am guessing there was a small amount of fluid and when the pump would go empty the engine would rev and the little amount of fluid would return and cause the rpm to lower. I have not tested this, just my opinion.