When modifications are made to a workflow model in AEM, they must be saved and synchronized with the running instance of AEM. If a user starts a workflow and does not see the recent changes or workflow steps, it could be because the workflow model was not synced in runtime. This means the running instance of AEM is not yet aware of the changes, and as a result, the workflow instance uses the old version of the workflow model.
Option B is incorrect because permissions would not cause the recent changes to be unavailable; they would more likely prevent the user from starting the workflow at all.
Option C is also incorrect because while errors in subsequent steps could potentially stop the workflow from proceeding, they would not prevent new steps from appearing in the workflow instance if they were properly saved and synced.