The PR Card applications are independent of each other. You are the primary applicant for your PR Card application and your dependents are the Primary for their respective applications.
Now coming to the approval part, IRCC may not necessarily process the application in group just because the applicants are from the same family, though they usually do (to the best of my knowledge). It could be possible that they are still processing your dependents application while yours was already done. It could be a matter of few more days and you should see change in their status too.
Was there any update on your dependent's application? Did they ever get the ghost update? It could be possible that IRCC did not accept their photos while your photo was good for processing. If there is any issue in the photo for your dependent, you should be getting a request to re-submit photos for them. This request can be in form of an email and/or a mail at the address provided in your application. I hope this helps.