would you explain about your modeling?what do you want to model?

I think you have to increase your mesh density. It looks like anisotropic material so this may be the problem with material orientation.

Probably a problem of postprocessing / extrapolation from integration points. Look at the scale of the stress bar, at the averaging criterion in your contour plot, look whether deformations are continuous and also think about what element type you are using.

Without more info, there is no way to tell.