Office 365 Outlook Task Categories Disappearing

A quick update.  This is definitely related to the Apple Watch.  If my Watch (series 3 running WatchOS 6.2.1) is off at 09:00, the categories don't disappear.  If my Watch is on, they do.  What's more, any status such as "Waiting for" against a Task is wiped out at 09:00 along with the categories.

I think this has something to do with the Today Notification feature added to Reminders at iOS 13.  By default this runs at 09:00, and it's as though this is still doing something to update the Tasks at 09:00, even if it is switched off in Settings.  When this syncs to Exchange, the Tasks are updated, minus Categories which, of course, Reminders doesn't support.  You can see the Tasks are being updated at 09:00 (by looking at the Modified Date through Outlook).

Further, even with my Watch switched off, if Reminders on my iPhone are lagging behind a bit with changes made elsewhere (and let's face it, they normally are), at 09:00 the version on my iPhone is "merged" with the version on my Exchange account.  For example, if I remove a Category on the Exchange Task and replace it with another, but the change hasn't yet sync'ed to my iPhone, at 09:00 the Category re-appears against the Task, alongside the replacement.

So, in summary, I think the sync'ing of Exchange Tasks to iPhone and Watch is pretty much screwed, and I have no idea how to log this with Apple.  And since turning off my Watch just before 09:00 every day is not really an option, I guess I'm back to switching off Reminders sync for my Exchange account until a fix arrives.

Jamil Haddadin, thank you!  I think this finally fixed it.  To be clear, I have a apple watch and iphone 5SE.  Both are up to date as to software.  I had already removed reminders from both devices, turned off notifications, to no avail. 

I went to settings, passwords & accounts, chose the account on which I have tasks (I have 3 accounts), and slid reminders to off.  I left calendars, emails, contacts on. Then I re-categorized everything, for the umpteenth time.  In the past, the task categories were disappearing about 9:00 am.  It is now 9:30, and so far everything is good today.

It's just that ToDo doesn't have categories, which started this conversation. With my business and the number of people I work with, I live in tasks, and everyone and every location have a category, to follow up with.

you have two options, you can use Microsoft Todo or TaskTask. I think you will love the first option!

The issue with TaskTask is the fact that it does not support Multifactor authentication (if your company is using MFA)

If I have tasktask app on my phone, will I still see tasks in that app,, since it syncs with Office 365 will I still see tasks there?