Recently, the growthexperiments-homepage-mentorship-question-disclaimer-mentor-away message has been added.
It prepends a default text to the mentorship requests redirected to another mentor while the current user's mentor is marked as away. (example: https://it.wikipedia.org/w/index.php?diff=145961742)
The default text contains a wikilink to the mentor's user page, resulting in a sent notification.
On itwiki we don't like this feature, and had to override the message. It probably would be better to either have an opt-out for the ping in the community configuration, or better, a single preference for each mentor. Thank you!