Feed rate changes during straight cuts

I tried cutting 1mm stainless steel on our Wazer recently and I noticed that the speed of cutting is changing a lot, even during straight cut segments. Is this supposed to happen? It repeatedly caused a partial cut as seen in the following picture.

I did not save the gcode but I have example from another WAM generated gcode where it also changes feed midst straight line. Same Y coordinate, increasing feed in quite discrete manner. I am not sure if there is some pressure increase that is supposed to follow this feedrate increase, but it does not seem like that.

Overall, I am having hard time to dial in good feedrates (through adjusting material thickness) that cuts through the material but does not completely obliterate the cutting board underneath. Generally, for a successful cut, I need to go very slow and the waste board gets shreaded very deep. I really hope this can be improved.