Different number of contacts syncing across my Apple devices

Hi Apple Community,

First, I am using the native iOS Outlook app to manage my contacts, as my primary email is corporate email and managed through my company.

I have used Apple for years and this is only something that has happened for the last year or so. I have iCloud configured correctly and am able to sync across my devices been set up for years).

I use my iPhone as my primary contacts syncing device with Outlook and my iPad has Contacts sync turned off. If I turn off Contact Sync in the Outlook app on my iPhone , it will delete all of my iCloud contacts. Not a problem. So I do that and start with a clean slate.

Sometimes there are some contacts left over that don't get deleted on some devices, so I ensure all devices, iPhone, iPad, 2 MBP and a MacPro are all cleared of any contacts. Additionally, iCloud on the web is also cleared of any contacts.

If I now, turn on Contacts sync in the Outlook app on my iPhone, it will ask to confirm syncing of 869 contacts. I confirm. 20secs or so later I now have 869 contacts in the native iPhone Contacts app. I check in iCloud on the web and there are 869 contacts in iCloud.

After waiting a little while, the iPad is now only showing 847 contact, MBP#1 has 861, MBP#2 has 867 and the MacPro has 854 contacts. I have tried turning off contact sync in iCloud on each device separately so that it would delete and re-load and the device will only sync the same number of contacts each time.

If I stop syncing from Outlook again and delete all contacts once again and do the whole process, the same thing will happen just with a different number of contacts that get synced to each device. I am unable to get all 869 contacts consistently syncing to all Apple devices. On another try, Phone - 869, iCloud on the web only listed 850 contacts, while MBP#1 showed 869, MBP#2 - 865, iPad Pro - 860.

What is going on?

It clearly is an Apple issue as all contacts are syncing to some devices.