I think often rescues go through phases. I might be completely overthinking it, but it's always seemed to me that there is a touch of the 'best behaviour' about the early stages. Maybe just because they've been in the rescue where they don't have their own space as much, often a lot of other cats around, and they probably need to be a bit more subservient, generally, than they might like to be.
Then they come home, and after a while they start to realise that they do have all these things, their confidence goes up and they start to express their real personalities more. But I also think at this point fears and things from their pre-rescue lives start to come out.
Food-based interaction is fairly common I think, and I think that's a good sign - she's not scared of you, and hopefully over time the base-line level of comfort with you, and desire to interact with you, will increase - that's what's happened with my mad cat, her first affectionate moments were food-related, but it's come on since then where now we get them for coming home, and very occasionally at random, and food time is an orgy of purring and headbutting. Meeting you in the hall is always a good sign I think, and I always find it a hilarious cat thing, the way they'll appear, but try really hard not to act like they were waiting for you. 'Oh, me? No, I was just sitting here behind the door, like I always do, nothing to do with being happy to see you DON'T TOUCH ME'.
Basically, don't worry too much! An isolated hiss and lash out could've been caused by anything. The only thing I'd look out for is if the hissing/lashing out seems to be related to touching her in particular places, as that could indicate pain.
I wouldn't force her too much, but do give her affection - just a gentle pat now and then when she's sitting in one of her spots, and pats at food times. Some cats are less/more affectionate than others and she might not ever be super into cuddles, but it doesn't mean they're unhappy. Or she might settle in and turn into a lap machine!