Rough edges on one side when 3D carving

https://youtu.be/x38OLicVF38

Any idea what might be causing the rough edges Illustrated in the video above? I tested my X & Y, by having it cut some circles and straight lines of different lengths and diagonal lines, and all of that came out perfect, so I'm going to test my Z today, I don't think I'm missing steps because the heighth is correct on the parts it's not like one part is a little shorter than the other or part way through it's cutting at a different height than before, it's just those scalloped edges.
Thanks!

It looks like something is moving or flexing,perhaps the whole workpiece because the bottom looks quite thin..Without more knowledge of how the piece is being held on the machine it isn't easy to understand the possible cause.The top surface looks good so if the sides are vertical,how about leaving a small amount on the outside to clean off with a very light profile cut?