When searching for message, the message content is displayed with some 'weird' text

As admin I went in My profile > messages and I sent some messages to a student (my message saying 'Hello student').
Then I searched the word 'student' and all resulting messages had the following text appended to the bottom:

--------------------------------------------------------------------- This is a copy of a message sent to you at "thisisthemoodleintegrationsuper...

Context

Note: very minor note, maybe context should be 'User discussions'. I didn't know what I was going to see before I clicked context.