I'm pretty sure you've found a feature, not a bug.
text.delimiter is the delimiter that is output after every
print call; by default this is
char(13), which is a line break. But a lot of the demos set this to something else — very often, the empty string — in order to suppress the line break. That's especially important if you're printing in row 0, since a line break there scrolls all the text up.
The demos should also set it back to
char(13) when they're done, but if you hit control-C or stumble on some other issue that causes the program to bail out early, you might end up with the delimiter not set. A simple
text.delimiter = char(13)
will fix it. (I can't remember offhand if
clear also resets it... if not, perhaps it should.)