zsh will not run scripts as /bin/bash even with #!/bin/bash as the first line

[John <da_audiophile@xxxxxxxxx>]

Been using zsh for a while now and loving it.  I ran into a problem today.  The following script errors out if run with zsh as my default shell:

#!/bin/bash
v_build() {

echo "The file is $1"
}

export -f v_build
find . -maxdepth 1 -type f | parallel v_build

Output:
% ./test 
zsh:1: command not found: v_build
zsh:1: command not found: v_build
zsh:1: command not found: v_build
zsh:1: command not found: v_build

If I switch to a user who has bash as its default shell, the same script runs just fine:

$ ./test
The file is ./test
The file is ./01.jpg
The file is ./02.jpg
The file is ./03.jpg

Love to understand what I have incorrectly configured.  It seems like zsh is ignoring the shebang telling it to use /bin/bash as the shell to run the script.