Why does git-svn redownload revisions?

For my first time using git-svn, I decided that I wanted to convert the GNU Nano Subversion repository to a git repo. I finally settled on the following series of commands after some initial trial-and-error (e.g. having the wrong `i18n.commitencoding` and not specifying a Subversion authors file): git svn init -s svn://svn.sv.gnu.org/nano git config svn.authorsfile ~/projects/nano/svn.authorsfile git config i18n.commitencoding 'ISO-8859-1' git svn fetch

The issue is that the fetch runs up to revision 4250, but then mysteriously
begins redownloading revisions 1 up to four thousand something in importing
the `nano_2_1_1` tag:
...
r4248 = 7c444dd667b9629ce92a53e8d35ad2d178e5735f (refs/remotes/trunk)
	M	nano/ChangeLog
	M	nano/configure.ac
	M	nano/po/cs.po
	M	nano/po/pt_BR.po
	M	nano/po/es.po
	M	nano/po/eu.po
	M	nano/po/hu.po
	M	nano/po/vi.po
	M	nano/po/nano.pot
	M	nano/po/ms.po
	M	nano/po/uk.po
	M	nano/po/ro.po
	M	nano/po/ru.po
	M	nano/po/rw.po
	M	nano/po/id.po
	M	nano/po/nb.po
	M	nano/po/gl.po
	M	nano/po/fr.po
	M	nano/po/nl.po
	M	nano/po/nn.po
	M	nano/po/pl.po
	M	nano/po/it.po
	M	nano/po/ca.po
	M	nano/po/da.po
	M	nano/po/sr.po
	M	nano/po/tr.po
	M	nano/po/ga.po
	M	nano/po/bg.po
	M	nano/po/sv.po
	M	nano/po/de.po
	M	nano/po/zh_TW.po
	M	nano/po/fi.po
	M	nano/po/zh_CN.po
r4249 = 6fbad8a00fa067d1e3de913f77db08c6117843c7 (refs/remotes/trunk)
	M	nano/NEWS
r4250 = 704700855e5112d75654e3e7461e896f49e10fd8 (refs/remotes/trunk)
Found possible branch point: svn://svn.sv.gnu.org/nano/trunk/nano =>
svn://svn.sv.gnu.org/nano/tags/nano_2_1_1, 4248
Initializing parent: refs/remotes/tags/nano_2_1_1@4248
	A	mkinstalldirs
	A	utils.c
	A	nano.h
	A	global.c
	A	configure
	A	Makefile.in
	A	AUTHORS
	A	configure.in
	A	ChangeLog
	A	proto.h
	A	nano.1
	A	nano.1.html
	A	README
	A	acconfig.h
	A	BUGS
	A	config.h.in
	A	ABOUT-NLS
	A	TODO
	A	INSTALL
	A	intl/po2tbl.sed.in
	A	intl/loadinfo.h
	A	intl/Makefile.in
	A	intl/explodename.c
	A	intl/VERSION
	A	intl/xopen-msg.sed
	A	intl/ChangeLog
	A	intl/finddomain.c
	A	intl/localealias.c
	A	intl/gettextP.h
	A	intl/textdomain.c
	A	intl/linux-msg.sed
	A	intl/l10nflist.c
	A	intl/loadmsgcat.c
	A	intl/libgettext.h
	A	intl/bindtextdom.c
	A	intl/gettext.c
	A	intl/intl-compat.c
	A	intl/dgettext.c
	A	intl/cat-compat.c
	A	intl/gettext.h
	A	intl/dcgettext.c
	A	intl/hash-string.h
	A	winio.c
	A	COPYING
	A	Makefile.am
	A	missing
	A	NEWS
	A	cut.c
	A	nano.c
	A	aclocal.m4
	A	install-sh
	A	po/cat-id-tbl.c
	A	po/stamp-cat-id
	A	po/es.po
	A	po/fr.po
	A	po/de.po
	A	po/ChangeLog
	A	po/Makefile.in.in
	A	po/es.gmo
	A	po/fr.gmo
	A	po/de.gmo
	A	po/it.po
	A	po/POTFILES.in
	A	po/nano.pot
	A	po/it.gmo
	A	stamp-h.in
r2 = 842a208235bd2a1181250766996f7797e74a8608
(refs/remotes/tags/nano_2_1_1@4248)
	M	winio.c
r6 = 280cfdcb8533ffcb424b3a86b7392ccfbc054e60
(refs/remotes/tags/nano_2_1_1@4248)
	M	ChangeLog
r7 = 6951e65102dd1e005761dec6eb082f0a2d9327a2
(refs/remotes/tags/nano_2_1_1@4248)
	M	AUTHORS
...

Why is git-svn redownloading revision history? Also, why hasn't git-svn redownloaded revisions to import other tags such as `nano_1_3_9`, `nano_2_0_0`, and `nano_0_9_14`? I have yet to complete the fetch, but git-svn finished redownloading revisions for `nano_2_1_1`, seemed to skip redownloading for `nano_2_1_2`, and is now redownloading for `nano_2_1_3`.