Check out my iPod "Car" theme:

Note how the progress bar does what you seem to describe. It does this on purpose there. I found, while making this theme, that anything on a line will wipe out the whole line of the progress bar, even a single space. So, if your theme is:
%P
^There's a space below the % there
The screen will look like this:
|---------|
|---------|
^There's a space below the % there
Which seems to be what you're describing. I don't know if remarks will do it, but I wouldn't be surprised.