https://helpx.adobe.com/acrobat/kb/acrocef-rdrcef-errors.html provides admins a method to close RdrCEF process when Reader has problems working with digital signatures. Users are unable to stop this process and with this in mind, can Reader be developed so that it terminates this process periodically, as it tends to start up when Reader is launched. Please note that this process is either in background processes or as a child process of Adobe Acrobat Reader DC, which on Windows 10 makes it a little tricky to locate immediately. If user is unable to unload this process, then it prevents users being able to digitally sign PDF documents as the dialogs are not presented.