I’ve updated the OP in this thread:
Update 11:10 a.m. PST - January 2, 2020
We continue to work through this issue, which is our top priority.
We’re working on a hotfix for the game that will resume Season 3, and at this time, we expect that we will be able to retroactively retain rating changes and tier updates. We do not expect that we will be able to retroactively retain the season games played count or win counts that increased during this brief offseason.
We’ll let you know once we have the final hotfix prepared, as we intend to restart all realms to deploy the fix.
Thank you for your patience.