My previous fix was mistaken.  Not sure why it passed tests; I
have two theories.  Regardless, it was wrong.  Current
`(org-outline-level)' seems the correct "LEVEL=" matcher argument to
make `org-map-entries' find only an item's immediate children.  (Operated
on by `org-reduced-level' of course)  I don't quite understand why.

Second, I may have solved the mystery of how the bug got by me before.
`org-map-entries' used to place point at the beginning of an item, a
fact which I used to recognize visiting the same item.  That seems to
have changed between org versions.

Third, I have fixed the real bug - properly now, I hope! - and
attached a patch.

Tom Breton (Tehom)