Sorry to hear that you've been experiencing issues since updating to PT 12.3. A few questions:
-Did this issue only occur when you updated PT 12.3, but NOT the plug-ins? I.e. you didn't install a newer version of the Eventide plug-in(s), but only PT.
-Have you restarted your computer since the new install of PT?
-What is the file path for the plug-in(s)? It should be /Library/Application Support/Avid/Audio/Plug-ins/Eventide on Mac, or C:Program FilesCommon FilesAvidAudioPlug-insEventide on Windows.
Make sure that the Eventide plug-ins are only in the Eventide subfolder, and that there are no duplicate versions in the Plug-ins parent folder.