How should a customer file a bug against f5 api?

The DevCentral contact form is generally for providing feedback and getting help with DevCentral-related functions, such as registration or login issues and broken links. For issues with F5 products, your best bet is to open a support case with F5 Support. Please refer to the article entitled K2633: Instructions for submitting a support case to F5 if you are not familiar with the process for doing so.