devtrackers.gg
That wouldn't surprise me if they were mistaken, I personally would hope so. While I don't necessarily have issues with the various battles being made canon, I'm not sure I'm big on it happening in general.
I believe it was /u/EA_Charlemagne who said it, but I haven't seen anything really clarifying. Last time I asked people didn't seem to care.
Battles themselves aren't canon, though they can draw from it or be inspired by different events. They're just multiplayer matches to us. Starkiller Base happened in canon, but in-game it's just our made up version. Geonosis happened in canon, but our battles aren't those and are just made up and based on parts of them.