Odd eating behaviour

Hi all,
I am wanting some tips/suggestions about a strange behaviour we have observed in our new rescue pup, Scout (shepherd x, 6 mths). At meal times Scout eats her food really quickly. I have never seen anything like it before, yet the vet has checked her out and she is completely healthy. What is really strange is that after eating she hides under the table until our other dog Dash (border collie x, 8mths) has finished eating. Dash is a very slow eater, who is prone to wandering off mid-meal and shows no food aggression at all. If Dash does walk away from his food, Scout won't come out from under the table until his food bowl is removed. The combination of the speed in which she eats and hiding under the table has us pretty puzzled. We don't know much about her background, but we were told that she clearly didn't have any socialisation prior to being surrendered (which is odd because she was surrendered with her sister).
She is an extremely affectionate and happy girl, so it is quite sad and strange to see her act this way only at meal times.
Has anyone experienced something similar before?
Any tips/suggestions on what might be causing this and how we can help her would be appreciated.
Thanks in advance!

Some dogs inhale their food, some eat slowly, I have some of each. Nothing to worry about. She may go under the table as she feels safer there at the moment. Don't pressure her to change, she will change her behaviours when she feels safe and secure, which could take time. Be relaxed about it all and pretend its not happening. Any efforts to remove her or stop her from what she is doing will make her even more stressed than she is now.

I've had dogs that inhale and dogs that like to savour every mouthful, I wouldn't assume anything about it tbh. As for lying under the table even when Dash walks away from his bowl, I'd consider that a bonus at least she's not diving in his bowl and starting a fight. Unless she appears scared I'd leave her to it.

It could be that she has had experience of a food guarder previously so the 'going under the table' is a safety mechanism for her even though she no longer needs it. I could also be that she has been trained to do it.

It really is nothing to worry about - in fact, it's quite a bonus

Thanks for your responses! It's very reassuring to know its nothing to be too worried about. We will try tawneywolf's suggestion of ignoring it until she is comfortable to come out. We had been trying to coax her out, with no success. Both our dog are rescues and sometimes I can't help but wonder where they picked up certain habits. I think I have to work on not dwelling on it too much though. Thanks again for your help!

Forget the coaxing, she will back off even more. Leave her strictly alone and let her make the pace. Whatever she does is normality for her and pushing her out of her comfort zone is not the way forward.
As has been said, this behaviour is a bonus. The Inhalers I have who finish in nano seconds, then walk round trying to steal off the slow eaters, who leave them in no doubt their attentions are unwelcome, they then graduate down to the puppy, but she has learned to inhale as well, and you should have seen the set of teeth she showed her Nana who approached her trying to steal her bone
Sounds like Peace Reigns to me, always a good thing