Odd behaviour with automator workflow

Hi there, i have a rather simple setup which causes a strange behaviour. It's two part, first a hazel rule, second an automator workflow:
Hazel-Rule
======
If all conditions are met:
- kind is archive
- name is xyz
- modified is not in the last two minutes
then
- run automator workflow
Automator workflow
=============
- New mail message (with some text)
- Get specified finder items (points to the xyz-archive)
- Add attachments to front message
It's the last step I can't cope with: Running the whole workflow as described I have two attachments of the xyz-archive in my mail. I have modified the automator workflow by omitting the last step and the whole workflow runs fine. Obviously omitting "add attachments to front message" sould make no sense.
So my question: why doesn't act the complete workflow (with the original automator workflow) as expected. And why does the incomplete automator workflow make sense here?
Hazel-Rule
======
If all conditions are met:
- kind is archive
- name is xyz
- modified is not in the last two minutes
then
- run automator workflow
Automator workflow
=============
- New mail message (with some text)
- Get specified finder items (points to the xyz-archive)
- Add attachments to front message
It's the last step I can't cope with: Running the whole workflow as described I have two attachments of the xyz-archive in my mail. I have modified the automator workflow by omitting the last step and the whole workflow runs fine. Obviously omitting "add attachments to front message" sould make no sense.
So my question: why doesn't act the complete workflow (with the original automator workflow) as expected. And why does the incomplete automator workflow make sense here?