Vimode problem (key press dropping)

[alx741@riseup.net]

ZSH users,

I'm using zsh Vimode for a while now, with a problem all the time:

When i hit ESC two times the next letter is ignored, so in order to 
enter insert mode i need to hit 'i'/'a' two times two. This is the same 
for any even number of ESC, the problem is the same for 4 hits but no 
for 3 times so i can say the second ESC hit leave the shell listening 
and it just drop the next key press.

I've already tried removing all my configuration and using a default 
config ZSH instance and then using 'bindkey -v' but the problem 
persists.

Am i doing something wrong?, thank you very much!

Greetings from Ecuador.