Dan, If the task IDs are still missing after clearing the filters as Larry recommends, then your missing IDs are most likely associated with “external” tasks in the linked sub-projects. Such tasks are hidden in linked master project views, and I’ve never found a way to un-hide them. You can confirm this by opening one of the linked sub-projects independently, with a view that displays the external tasks.
(Note: when you have a logic relationship between tasks in two different projects, an “external” task record is inserted into each project. Within each project, the external task represents the opposite end of the logic relationship; it provides a data link to the task in the other/source project and duplicates some of the associated task information. The duplicated information is used to mimic constraints of the relationship when the linked project is not available. Sometimes these are called “ghost” tasks.) Good luck, tom