If the colors you've chosen are not fully saturated, the items were likely created in wireframe mode. Wireframe components use toned down, more transparent colors by design, so they won't be fully saturated. This helps keep wireframes semantic (primarily about the content and layout).

If you need more vibrant colours, you could add shapes from the flowchart range - they will be true to the color you've chosen from the palette. Here's an example of color differences between flowchart shapes and wireframe component: