In mod_lesson_renderer::progress_bar() there are 3 start_tag divs but only 2 end_tag divs. The browser usually handles this by filling in the missing div but in some cases it might make elements move around.

This doesn't look to be an issue in theme_boost but in a custom theme we use it is causing an issue and an element ends up in the incorrect place.

Best way to test this is to use xdebug and check $content has matching open and closing div tags.