Was this FAQ an official Forge World release? I only ask because I noted that on the FAQ sheet itself it says "With thanks to the members of Chaos Dwarfs Online...". So is this FAQ official GW/Forgeworld or fan made?
---------------Yes, it's official! Chaos Dwarf Online merely provided a lot of feedback.
All of the Official GW FAQs for the 8th edition of Warhammer Fantasy Battles are presented below as downloadable PDFs.
If you don't see a particular army book or supplement, that means that no FAQ or errata was ever released by GW. Note that each document was the most recently updated FAQ by GW. For clarity, the above statements are FACTUAL, it cannot be argued.
For further clarity, army books published after April 2013 do not have any updated versions (any updated version for these armies found on the internet are in fact for the overlap of 7th edition army book/8th edition BRB).
There has not been an English one, but there were Updates for some non-English versions. For instance, in the German Update version there was a single Erratum to change the points value of the repeater handbows upgrade for Black Arc Corsairs from 4 into 2. This did not need correcting in the English version.