Color Alone, Color Contrast, Color Conflicts

Position (continued)

Is a color difference between a visited link and an unvisited link a failure of Use of Color?

From Non-text Contrast:

there is not a new requirement that visited links contrast with the default color

Also from Non-text Contrast:

does not require that changes in color that differentiate between states of an individual component meet the 3:1 contrast ratio when they do not appear next to each other

Does it need to meet the 3:1 contrast ratio when they do appear next to each other? If so, how much is "next to each other?"