The recalculation is being processed in parallel across the entire network. Since it's run per user, some users on a site might get the change before others. We also had technical difficulties that have slowed the process down a bit. Hopefully it will be done for everyone across the network in a few hours. (Hopefully not days, but I can't rule that out at ...
The procedure appears to be:
1) Have third-party cookies turned off.
2) Log into MathOverflow with the desired account.
3) Clear all cookie data for all sites ending in stackexchange.com
4) Log into ***.stackexchange with the desired account.
The order very much matters.