Why is my Stomach Doing This?

I am 45 and I have had 6 pregnancies. I had a mini tummy tuck along with an umbilical and diastisis repair in 2019. I was elated with my results initially. Now I have developed what can only be described as a "shelf" on top of my scar. When I sent these pictures to my PS I was told to come in for an exam. He is 2 hours away so I thought I'd ask here first. I did see a local PS about lipo but was told there is no fat in this area? What is my stomach doing this?