Has Exchange on-premise 2016
Password Writeback enabled in ADconnect
Assigned Azure AD Premium Plan 2 to user1
Enabled Self Service Password Reset in Azure AD
When user1 tries to reset his password using SSPR, the new password reflects in AD and user1 can login to on-premise OWA using the new password. But if the Office 365 Admin will reset user1's password in the Portal the new password works in portal.office.com (Office 365) but not in on-premise OWA. I tried to re-sync AD but didn't work. I also used PowerShell to enforce password sync but no to avail.
Am I missing something? Any idea is appreciated.