Very often, on my Mac, when I use the pipe (|) character followed by a space character, an invincible character will be inserted in between.

This is especially annoying when using the terminal, as it makes commands invalid.

If I type the following in iterm2, I often get the following:

ls | cat
zsh: command not found:  cat

If I hit the up-arrow-key to get my previous command, and then remove and reinsert the space between | and cat, the command will work.

When I copy paste the working and non working commands into a file, like this:

non-working: ls | cat
working: ls | cat

and open it in Hex Fiend it shows the following:

non-working: ls | cat
working: ls | cat

I've also experienced the same kind of issue in SublimeText2 using the square brackets ([]) followed by a space. So I don't believe its an issue with iTerm2.