Watchdog gets three events in Python 3

Question

Watchdog gets three events in Python 3

I am creating a Python program using Watchdog that tracks a set of files and takes action based on changes. I put the exact example from their site into a file:

import sys
import time
import logging
from watchdog.observers import Observer
from watchdog.events import LoggingEventHandler

if __name__ == "__main__":
    logging.basicConfig(level=logging.INFO,
                        format='%(asctime)s - %(message)s',
                        datefmt='%Y-%m-%d %H:%M:%S')
    path = sys.argv[1] if len(sys.argv) > 1 else '.'
    event_handler = LoggingEventHandler()
    observer = Observer()
    observer.schedule(event_handler, path, recursive=True)
    observer.start()
    try:
        while True:
            time.sleep(1)
    except KeyboardInterrupt:
        observer.stop()
    observer.join()

Then I noticed something strange. I also set a watchdog for both Python 2 and Python 3 (using pip2 install watchdogand pip3 install watchdog) and at the same time. However, when I run the program in Python 2 and 3 and do the same modification once for each, this happens:

$ python2 watch_test.py
2015-09-30 11:18:32 - Modified file: ./watch_test.py
$ python3 watch_test.py
2015-09-30 11:18:39 - Modified file: ./watch_test.py
2015-09-30 11:18:39 - Modified file: ./watch_test.py
2015-09-30 11:18:39 - Modified file: ./watch_test.py

What interests me is what can cause this behavior and how can I fix it.

This question is not a duplicate: