Jacob Keller [off-list ref] writes:

From: Jacob Keller <redacted>

If a commit in a sequence of linear history has a non-monotonically
increasing commit timestamp, git name-rev will not properly name the
commit.

However, if you use --annotate-stdin then the commit does actually get
picked up and named properly.

IIRC, this is to be expected.

When preparing to answer --annotate-stdin request, the command has
to dig down to the root of the history, which would be too expensive
in some repositories and wants to stop traversal early when it knows
particular commits it needs to describe.

Dscho?  I think this is pretty much a fundamental part of the
initial version added by bd321bcc (Add git-name-rev, 2005-10-26) and
kept that way to this day, I think.