Updated to Opera One version 100.0.4815.21 yesterday. Synch seemed to have changed/stopped synching but was still showing as signed in but without the profile picture. Synched it and lost a workspace with all the open tabs.
Today, opened the browser and all open tabs from yesterday are gone (setting to keep tabs from last session is still enabled). Synch says it is synchronized and profile picture is showing. Other things, like bookmarks and pinboards are still there (but don't know how updated they are).
Operatin System information:
Edition Windows 10 Home
Installed on 21/07/2020
OS build 19045.3086
Experience Windows Feature Experience Pack 1000.19041.1000.0
Opera version: 100.0.4815.21