I think there is a glitch on text area.
I was not able to determine the exact cause, but I have seen a lot of posts with repeating words such as "suchsuch", etc.
Just on one occassion you can clearly observe what I mean: when you try try to mention a user, after typing (at) sign and first few letters, a selection of text pops up. If you click enter or select one of the suggested users, you can see the repeating text. e.g. "@[email protected]"
Hope above make some sense?