Yes, I think that's pretty common.
I used to wonder about that paradox myself: If the show is free to ignore what the books do anyway, why should they impose any restrictions on what the books do? I finally realized it's because the purpose of the books is to support and follow the show, not to pre-empt it. If there's a story the producers think they might tell, they want to be the ones to tell it, not to have a tie-in steal their thunder. If a tie-in has already told it, they'll go ahead and ignore it, but if they have the opportunity in advance, they'll say "Don't do that before us."