I would think that the spindle apparatus are simply just starting to pull the chromatids apart, either that or they haven't fully lined up yet and it's slightly before metaphase
Under a microscope, some of the cells can seem to be present in between the metaphase and anaphase as chromosomes on the metaphase plate are held tightly with the help of pulling and pushing forces from the microtubules.
The metaphase can cover a bigger part of the entire duration of mitosis as the alignment of the chromosome at the middle of the cell on the metaphase plate functions as a checkpoint for getting advanced into the next level, that is, the anaphase.
The cells can arrest in metaphase for much time, until and unless the chromosomes get aligned appropriately and the cells enter anaphase.
