Over the past few days I was struggling with a problem regarding really simple captcha causing my gravity forms to truncate any HTML following the gravity form's included css files.
I ended up figuring out that really simple captcha uses win_is_writable(), which is found in /wp-admin/includes/misc.php. All I did to fix the problem was put
at the beginning of really-simple-captcha.php
This was happening on a multisite, not a regular wordpress install.
I hope this will help others in the future