Problem-1 is as follow:
1. OneDrive does not sync files larger than 3 GB
2. OneDrive does not always sync files between 1.5 and 3 GB. 10-20% goes through and 80-90% goes in circle. Circle means it sync the file until the end, and then it start all over again and it sync the same file again and again and again…..
3. OneDrive does not sync always files between 1 and 1.5 GB. 50% goes through and 50% goes in circle. Circle means it sync the file until the end, and then it start all over again and it sync the same file again and again and again…..

The problem we found was as follow:
The same server, and the same folder was previously synced with OneDrive from Office 365 Home Edition. And now we are syncing the same folder with OneDrive of Office 365 Business edition, and apparently this is causing a conflict that we were not able to find due to it will take more time than it is worth it.

The workaround
I created a new account on our server and used this new account to sync the same folder with the same structure as before, and it works perfectly, no more circling and all files goes through 100%, including ISO files that are up to 6 GB and ZIP files that are up to 12 GB.

Problem-2. small problem that I was not able to figure out why it is happening. Every a couple of hours or so, the sync stops for around 5-30 minutes and then it continue by itself. Sometimes I just pause it and immediately restart it and then it keeps on going. But this is not a huge problem, except at the initial sync, where around 600 GB are being synced and that can take around 10-14 days, during this period it pauses by itself, which it delays the overall sync by around 2-4 hours per day= around 2-4 days. But after the initial sync, then the update is always minimal. So no problem I can live with this un wanted pauses.

I worked on Problem one for 3 weeks with OneDrive Technical support until we were able to pin point the problem and use the workaround.