Display message box only if "filter finder items" finds an item (Automator)
It is doing the right thing. 

There is no decision making being done so the dialog box will appear every time. To fix it, you will need to add an AppleScript action as discussed here

https://discussions.apple.com/thread/509298?start=0&amp;tstart=0

So, if the filter returns an empty list {} then it quits. 

Here is what it looks like...