I wrote a Pywikibot script that adds a message to a user’s talk page if some conditions are detected. So far so good, but when my bot leaves the message, the user is not notified, which kind of defeats the purpose. The bot account operates with the bot flag.
I tried adding a notification in the message, as in Hey [[User:Someone|Someone]], but this does not trigger a notification either.
Thanks to @axo, I found the solution: in order for the user to be notified, the edit that adds the message to the user talk page must not be minor, so:
user_talk_page.save('Hey there', minor=False)