Yeah, I had that issue a little too. Not too sure what caused it, but I don't believe that it is an issue with the model. I will look into what caused it and then get back to you on why that has happened.
So apparently it is due to insufficient cooling, where the material warps around the infill of the object. It would make sense that if it was warping, that would be due to not enough top layers, however, if you preview it in the slicer you can see that there is internal solid infill so there are about 4-5 layers on the top (I have attached a picture for you too see). So overall, not too sure what caused that then.
Yeah, I found that there was some pillowing on the front of mine, but I wasn't too sure how to get rid of it in the slicer. I'm glad it works though for you. 😀