RE: Nonexistent changes appear rebasing but only with rebase.backend=apply

Marco Giuliano wrote:

This might not be caused by rebase command itself, but rather by some
previous operations which might have accidentally "broken" something
and that the rebase simply makes them appear.
You need to know that commit 4 is the result of several squash and
reordering of multiple commits; is it possible that some of those
operations have created some "leftovers" ?

Smells like the reflog.

Have you tried --no-fork-point?

-- 
Felipe Contreras