I have the the most recent versions of DJO and CL Express.
All categories and folders are set to sync bidirectionally.

None of my tasks modified on the phone were making it back to Outlook.
I deleted all Outlook tasks, and set a one-time Android-to-Outlook overwrite.
All but three of my many undated tasks are not showing up in Outlook.
A task deletion and a due date modification have synced with Outlook now.

Any advice to get the rest of the undated tasks to sync with Outlook?