QUOTE(Scremaz @ Apr 14 2016, 18:40)

btw, which was the reason? just curious...
It was one of those really subtle things. The rating/favorite update required a change to how the database handler deals with null values, and as a consequence, queries that try to insert a null value into a schema that is defined to not allow it will now fail. Now normally, failed queries will show up quite loudly in the error log, but some of the queries Galleries does on the forum database have a special flag that makes the database handler ignore errors and continue if the query fails - this is to prevent cascading failures if the forum database becomes unavailable for any reason. So, when the system tried to update the forum record of someone who didn't have a donation badge - which internally happened to be represented as a null value - it would just silently fail, as the forum's database schema for that table doesn't allow one.
And, since both the accounts I was testing it with had a badge, everything appeared to be working for me.