Strange text message

I sent my wife a fairly normal text yesterday, she replied to it and asked a question (what film I was watching on my ipad) which came out of the blue to me so I obviously asked her why she suddenly asked since I didnt say anything about watching a film...

Long story short the text message I sent to her from my phone displayed the message I sent however on her phone somehow an extra line of text was added stating that I was watching a film on my ipad.

I did not write this, no one else had access physically to my devices at the time.

Has this ever happened to anyone else?