The property in question is AfterInitialDemand. The screenshot of the job is below. The question is what exactly AfterInitialDemand is for apart from the formal definition reading that it's a sub-key overriding KeepAlive, RunAtLoad, WatchPaths and StartCalendarInterval keys and making the job run only by starting it manually? First, when I loaded the job and then tested it against a watched file Console reported smth to the effect of "Unknown property for RunAtLoad" and "Unknown attribute for KeepAlive" (or vice versa, don't remember). The job ran and exited with success, though, doing what it was expected to - I verified that by creating the situation several times.
The watched path is /Users/home/Library/Preferences/com.apple.applescript.plist
The watched path is /Users/home/Library/Preferences/com.apple.applescript.plist