automount does not recognize options from NIS map

[geek65535]

Ubuntu 12.04, autofs5 5.0.6

automount recognizes mount options given in a local map.
Eg, /etc/auto.home:
* -vers=3 myserver:/home/&

But the same options in an NIS map are not parsed correctly.
# ypcat -k auto.home
* -vers=3 myserver:/home/&

With BROWSE_MODE="yes" in /etc/default/autofs, the above line in the NIS map will produce:
# ls /home
-vers=3

That shows that, rather than parsing the options when they are there, automount is taking the first whitespace-delimited string as the mount arg.