I found that certain unresolved issues which appeard in ALL, did not appear anywhere else, like under open issues byu assignee. The only other way to access the issue was to directly key issue # into quick search.
We found teh issues to have a due year of "0005" instead of "2005". I tried to reproduce this by entereing 05 and 0005 into year portion of due date but I kept getting errors.

This is CRITICAL as it means we cannot rely on Jira to track our issues without inadevrtantly dropping one or 2 or 3 or 20 ....