Consider the following rsync -aH:

bob# rsync -aH bob:/opt/src/git-doc .
ABORTING due to invalid path from sender: git-doc/.vale/vale.tmpl
rsync: connection unexpectedly closed (322182 bytes received so far) [receiver]
rsync error: error in rsync protocol data stream (code 12) at io.c(232) [receiver=3.4.0]
rsync error: requested action not supported (code 4) at flist.c(2693) [generator=3.4.0]
rsync: [generator] write error: Broken pipe (32)
bob#

Now consider this:

bob# rsync -a bob:/opt/src/git-doc .
bob#

3.4.0 has broken preserve hard links.