Bethesda was suing Behaviour and Warner Bros. for "copyright infringement, breach of contract, and misappropriation of [Bethesda's] intellectual property". Behaviour Interactive aided in the development of Fallout Shelter, and Bethesda stated that the Westworld mobile game "has the same or highly similar game design, art style, animations, features and other gameplay elements as Fallout Shelter". What the details of that settlement are nearly certainly will never be known, but it's likely safe to say that it netted Bethesda a certain amount of money or a percentage of sales from the Westworld Mobile app.
In a press release, Bethesda said it has reached an agreement with Behaviour Interactive who developed the Westworld game and Warner Bros. Behaviour Interactive worked on both Fallout Shelter and Westworld, and Bethesda alleged that portions of code, such as this, were shared between both games (theirs first). Bethesda sought damages and the shuttering of the Westworld game. Entertainment, which is the publisher of the title. A December 12 ruling confirms that both sides had resolved the issue and will pay their own costs, and the claims have been dismissed with prejudice by Bethesda, so that they can't be made again.
On top of that, there were some bugs in Westworld that were in an earlier version of Fallout Shelter, making a strong case for Bethesda's claim.
The lawsuit that Bethesda brought against developer Behaviour and media giant Warner Bros. over a Westworld video game has come to an end, it seems. It even called Bethesda's allegations "untrue" and "baseless" at the time.