Someone here on the forum has already realized that when the shading is grouped when it grows it distorts the pixels, if it is not grouped it looks good. I know that this error is happening in Corel 2020 and 2019, in other versions I don't know.The new internal shadow effect of Corel 2020 even grouped does not happen this error when making it bigger.Does anyone know any solution to this problem?I made a sample video
Try saving the document, then opening it.
You could also try changing the rendering resolution of the document, then changing it back. That seems to update the appearance of the Shadow effects.
saved and open, did not solve
(change the rendering resolution of the document and change it again) I didn't understand about that