Rounded corners appear darker

[star_space]

For whatever reason my rounded corners appear darker both on shapes that have a drop shadow and shapes that do not. Before this problem I had a black stroke applied, but when I removed the stroke, this is what it looks like. Could someone give me some insight on how to fix this?

[c.pfaffenbichler]

Please provide the file or at least a meaningful screenshot taken at View > 100% with all the pertinent Panels visible.