Weird completion behavior in middle of word

[Khelben Blackstaff <eye.of.the.8eholder@xxxxxxxxx>]

Hello.

I have enabled complete_in_word because i use completion in middle of word 
frequently. I noticed a behavior for some time but didn't ask here because
i don't know how to describe it correctly. Nevertheless i will try to.

When i try to complete in the middle of a word, sometimes the whole word
is deleted. It doesn't happen every time though. I have the impression that it
only happens when the pattern contains "../"

For example, consider the following:
% mv ../geo-old/* .

Lets say i want to change "geo-old" to "geo-new" then i will move the cursor
to "o", type "n" and then press tab. The normal behavior is to give me
"geo-newold" which happens correctly if there is no "../". In this case,

% mv ../geo-nold/* .  (cursor is after the n)
if i press tab now the whole "geo-old/*" is erased and i get
% mv .. .

I have also captured it in video, but it is 40K so i don't know if it is
proper to attach it here.

My first guess was that i have something wrong in my configs, but i don't
have many stuff. The zsh version is 4.3.10

The relevant options in my config files are the following:
[zshenv]
setopt complete_in_word
setopt extended_glob
setopt magic_equal_subst
setopt no_nomatch

[zshrc]
zstyle ':completion:*' use-compctl false
zstyle ':completion:*' group-name ''
zstyle ':completion:*' ignored-patterns '_*'
zstyle ':completion:*' completer _complete _prefix _files

Other statements are declarations of variables,aliases,etc.

Thank you for your time.