For me XTerm (vsn 337 on Gentoo), I got the unpatched zsh -df show "after
2" which I take it differs from your results.  I also got rxvt-unicode-9.22
to have the unpatched zsh -df put the curser just after the 2.  OTOH,
trying "st" (simple term from sucksless), I got the incorrect position "on
top of" the 2.  You may also want to check the terminal emulator in PuTTY.
HP-UX and AIX terminals were always "odd", but those are harder to get
access to.