If things have changed, I think it makes sense to ensure the FAQ is updated to reflect the latest information. The primary purpose of the FAQ is to accurately inform people of what the game is like now.
Oh I completely, fully, and 100% agree with that. Precisely because the FAQ is an FAQ. But it's not the destination I disagree with, it's how it's reached.
As RagnarokCzD mentionned, Larian could have kept a note of what changed. Or even just struck out the out-of-date information.
I get what you're saying, but I still fear this is an overreaction. In cases of stuff like Spiritual Weapon it was probably a mistake and they have no obligation for clarification any more than they have to throw their hands up and spill the beans in detail because some dataminers found stuff.
Props for them for even keeping it updated, as most studios just leave it without a damn care. It's been 3 years since EA alone, so of course stuff changed. I think you're looking at this from a way more negative perspective than warranted and nothing removed or changed so far is 'shady' or worthy of elaborating on with any reasonable amount of context that wouldn't get anyway upon release.
I very much doubt spiritual weapon existing or not will move sales figures, for instance.