Short option autocompleted with an extra equal sign (Bash)

[born4new]

Here is my test program:

Usage:
  #{__FILE__} [--test=<test-value>]
  #{__FILE__} -h | --help | --version

Options:
  -h, --help               Shows this screen.
  -v, --version            Display the program version.
  -t, --test <test-value>  My own test value

Here are some use-cases for the above program (I'm using docopt.rb here):

# Valid case: long option with equals sign
./docopt-test.rb --test=1234

# Output
{"--test"=>"1234", "--help"=>false, "--version"=>false}

# Valid case: short option with a space
./docopt-test.rb -t 1234

# Output
{"--test"=>"1234", "--help"=>false, "--version"=>false}

# Invalid case: short option with an equal sign
./docopt-test.rb -t=1234

# Output (the value is =1234 here)
{"--test"=>"=1234", "--help"=>false, "--version"=>false}

Here is the autocomplete file I get when using this tool:

_docopttestrb()
{
    local cur
    cur="${COMP_WORDS[COMP_CWORD]}"

    if [ $COMP_CWORD -ge 1 ]; then
        COMPREPLY=( $( compgen -W '-t= --test= -h --help -h --help -v --version ' -- $cur) )
    fi
}

complete -o bashdefault -o default -o filenames -F _docopttestrb docopt-test.rb

It basically only autocompletes with -t=, which is an invalid option as far as docopt is concerned.

Is this a problem on my script or could this be a bug?