The one point on which Wiccan traditions genuinely disagree about the threefold scheme is whether the aspects correspond to biological stages of a woman's life. The straightforward reading, and the one implied by the names, is that Maiden, Mother and Crone map onto youth, childbearing years and old age. That reading has been pushed back against for decades, most sharply within Dianic and other feminist influenced lineages, on the grounds that it makes the Goddess a description of a reproductive career and leaves out women who do not follow one.
The alternative treatment is to take the three as symbolic postures available to any practitioner regardless of age or sex: the Crone as the stance one adopts when the work in hand is judgement or release, not as a report on how old anyone is. Both readings are in current use, and covens that share almost everything else can differ on this. Ronald Hutton, in his history of the movement, describes the range without adjudicating it, which is the correct treatment for a live disagreement inside a living tradition.
That disagreement is worth recording rather than smoothing over, because it is one of the places where a modern religion can be watched deciding what its own symbols mean. The atlas holds the Crone as an aspect of one Goddess, notes that the mapping onto life stages is contested inside the tradition, and leaves the question where the practitioners have it.