Chat limit

[vegetagz6]

While I engage in chat with someone through a mobile device, if I am typing a long message, it automatically gets send once I reach some character limit. Is this happening for anyone else, I noticed this in android tabkets and sometimes in laptop.
Last this happened when I was typing a message over 1200 characters, it automatically got send, before I could finish it.

Is this a bug or is this limit on characters imposed by default?