Acol Confusion?

This is another confusing bidding by Lia, the IntoBridge robot. Actually, it is a bit annoying. I am playing Acol again to unburden my brain a bit from all that Gavin Wolpert stuff. So, 1NT is weak. After the 2♠ intervention and two passes, Lia doubles. In view of its shortness in spades and support for any other suit, it is a brave decision. I dutifully answered 3♥, and that would have been a good contract. In fact, I made 9 tricks.

But can anybody tell me what drove Lia to go to game now? In fact, we have 20 high card points together and flat hands. Lia also has defensive values. So there is no reason to assume that 3♠ would make. But even if, 4♥ cannot be pre-emptive here. So, the robot must have fancied that the contract has good chances.

A look into the description of the bids reveals the reason. My 3♥ are described as forcing, 6-card and a slam try. The double, by the way, is described as take-out, but not forcing. That is to allow me to transfer it into a penalty double. I can't in this hand. In the end, I have no idea what I should have bid instead.

On the other table, the bidding went completely differently, of course.

This went down one. I am not sure if South should have bid 3♥ here. But it would not make a difference, because West might have raised anyway.