Hope you are doing well and sorry for the trouble. As described, When you try to reorder the containers in the reading order panel the app crashes.
Is this a behavior with a particular PDF file or with all the PDFs? Please try with a different PDF file and check? If the file is stored on a shared network, drive please download it to your computer locally and check.
Also make sure you have the latest version of the Adobe Acrobat DC installed. Go to Help > Check for Updates and reboot the computer once.