Strange message from nonexistent Dgrin user

I received a message notification for a post from Dgrin, this the content:

jonusb3 has just replied to a thread you have subscribed to entitled - I don't receive notifications anymore - in the Dgrin Forum Support forum of Digital Grin Photography Forum.

This thread is located at:
..................................................................

Here is the message that has just been posted:
***************
CANCELLED
***************
There may also be other replies, but you will not receive any more notifications until you visit the forum again.
All the best,
Digital Grin Photography Forum

Besides the weird (...) content of the message itself, two things:
-the user is not registered at Dgrin forum (search fro user gives no result)
-the post is not where it should be
Can somebody explain me this?
Fabio