The easiest way to test this is to manually change the window's title. For example, the following command works to change the window's title when using gnome-terminal:
When this same command is run through Guacamole, part of the new title is printed inline on every line (everything save for the first alphabetical character), and resembles artifacting:
...NB: if you run this same command inside gnu screen, the output is slightly different (note the subsequent command prompts lack the same title artifacting)
...furthermore, if you detach and reattach to the same gnu screen, the artifacting is gone.