We have the same issue with DEP enrolling duplicates to some devices. The only fix we have found, temporarily, is to do the following:
1. Batch upload your devices to the console
2. Confirm the upload and assignment in Lifecycle
3. Assign a DEP profile to the device(s)
4. Log into Apple Business Manager, and assign the devices to your server
5. Go back into your console and Sync Assets. Confirm the device is still in LifeCycle and not duplicated.
6. Assign a DEP profile to the device(s) AGAIN. (You may find that the DEP profile is no longer present after the sync)
Only after completing these steps were devices able to enroll properly. Before that, we would get duplicates and sometimes they would enroll as a staging user instead of the intended user.
Also, if you have duplicates, remove them in Lifecycle by un-assigning the devices in ABM, and then Sync Devices with Apple in the console.
Then complete the steps listed above.
We are experiencing the same issue more and more often.
Invalid Profile errors during setup. It used to be maybe 1-3 out of 100 now it seems more like 10-20 out of 100 with this problem. We haven't touched the DEP Profile in ages, so the issue isn't due to any config alterations. Also, the same iOS-device with this profile issue will suddenly work fine after a factory reset.
This is a major issue for us since we send devices all across Switzerland and expect the users to set their iPhones and iPads up themselves. If they happen to receiver a problem device, we cannot expect them to reset their device with iTunes or Apple Configurator. In one case we went through 3 iPhones with the same user.
I even tried to open a ticket with Apple - but they aren't any help unless you shovel cash for a support contract over to them. Apple Switzerland's lead engineer said he had never heard of this problem, which I highly doubt. Useless.
I’m really looking forward to Workspace ONE supporting COPE-Mode for Android so we can finally kick iPhones out.