Hi, I have the same Issue. On Iphone (10) is Version 6.4.1 and on Windows 6.4.
I have already disconnected, deleted and installed from scratch, fresh installed and completely resynchronized both device from fresh backup file.
The restore from backup file works.
But once I enable sync with onedrive I get 2 Folders in my App Directory
App/Enpass
App/Enpass 1
When trying to Sync on windows the error is "Could not find Enpass6 Data on Onedrive" ( was in german, translated)
I am a registered User.