Safari extension - loading second instance of DTP

Using DevonThink Pro Office 2.11.2 / macOS 10.14.4.

Today, on one 1 Mac when using the DevonThink extension in Safari (whether using the shortcut key or clicking on the icon in the toolbar) after getting past the “Do you want to allow this page to open “DEVONthink Pro”?” instead of showing the black ‘Clip to DEVONthink’ window, a second instance of DTP is loaded and then the ‘clip to DEVONthink’ window appears.

However the ‘Clip to DEVONthink’ window does not work:

  1. the top entry where you can specify where to store the clip is blank and clicking on it does not show any options; and
  2. pressing on Clip CommandS button also not respond.

I have tried uninstalling the Safari extension and reinstalling, rebooting the machine etc but the problem persists.

You cannot open a second instance of the application, so you must have another copy on your system.
Do a Spotlight search for kind:application devonthink