[Kevin Yank]

I can reproduce it reliably by setting ScanSnap Manager to create a PDF file in a folder with the Folder Action attached. Scan a page, then wait a moment while ScanSnap Manager prompts you to insert another page or click Finish Scanning. The Folder Action is triggered at that point, even though you may have more pages to scan.

I’ve found a perfect solution, though: Use Automator to create an Application containing a single Run AppleScript step with the following code:

on run {input, parameters}
if (class of input) is not equal to list then set input to {input}
try
repeat with i in input
tell application "Finder" to set file_name to (name of i)
tell application "OmniFocus"
tell quick entry
open
set NewTask to make new inbox task with properties {name:file_name}
tell the note of NewTask
make new file attachment with properties {file name:i, embedded:true}
end tell
activate
end tell
end tell
end repeat
end try
return input
end run

Save the application in your Applications folder, then set up your profile in ScanSnap Manager to open the scanned document using your new application.