Quest 11120 in the Brewfest event is only available on US servers.
Would it be possible to filter it out from EU servers as it currently counts towards the 83 total for Brewfest.

No idea how to filter it out just yet but this quest wasn't tagged as yearly in the last release (only was fixed 5 days ago c606716) so that's why it was counting. We put notes on all quests that are not available in EU and they are all repeatable so shouldn't impact your count.
You can download latest in-development version with all Brewfest fixes here.