Cannot remove user mailbox photo

Hi to all,

i need to remove mailbox photo for a user and i have no success.

- Photo is already removed from active directory

- Tried command: Remove-UserPhoto "xxx"

- Tried command: Set-Mailbox "xxx" -RemovePicture

Commands runs ok, but the photo is still visible. ONLY for one specific user. I tried with other user and the change is immediate.

I'm running Exchange 2013

Thanks for help!