The visual artifacts are typically when one group (here control) is sequenced at much lower depth than the treated group in a two group comparison. The patterns are unavoidable. It is not great to have large differences in sequence depth across the conditions, but I don't have a decision boundary or anything at which it's too much of a problem. I would zoom out on the plot (e.g. to [-6,6]) so you can see which genes are being called DE if any.