I have made several models that [should be] completely flat on the top, but the top edges are very slightly rounded upwards. The rest of the top is very smooth (I have Enable Ironing set to True). One thing I have considered trying is setting Ironing Inset to 0 in hopes that it will flatten that area out, but that doesn’t seem like it should be necessary. Any ideas?
Is it really only on top? It sounds a bit like warping, but “classically” warping happens at the lowest layers first.
Do you have a photo?