In the problem line:
<?php
<p class="project-subject"><?php echo the_field('top_post_content')['title']?></p>
you may want to replace the_field with get_field, or omit echo.
I take it, top_post_content refers to a post. In the back-end you can pick if you want the field to return a post object or merely the post ID, in which case it will not return the title. You could use:
<?php
get_the_title( get_field('top_post_content') )
