Thanks for your update.
Have you try to uninstall and reinstall the smart card manager to see if the issue still exist.
If the issue till existed, we need collect some necessary traces to figure out why the service was stopped. If your issue is urgent, I would suggest you open a case with Microsoft where more in-depth investigation can be done so that you would get a more satisfying explanation and solution to this issue.
Also, in this way ,they can have a clear picture about your issue and your environment by phone communication and live share session.
You may find phone number for your region accordingly from the link below:
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