Hi everyone, have you ever experienced blocking the AR, AP, and the rest options for a specific accounting period and still being able to perform transactions? What could be happening and how can it be corrected?

Those roles have the 'override period restrictions' permission. This enables posting to a locked period. You haven't forestalled all posting until you've actually done the very last step of closing the period in the period close checklist. You can remove that permission from those roles if they shouldn't be able to post to locked periods, but presumably there are some roles that need to do some final posting after everything is locked. Probably worth reading this to get more familiarity with the close process: https://suiteanswers.custhelp.com/app/answers/detail/a_id/7648/loc/en_US