I honestly think this is an oops, not a rights grab, but I am certainly not submitting to them again until they change it.
If you do submit material, and unless we indicate otherwise, you grant FantasyScroll and its affiliates a nonexclusive, royalty-free, perpetual, irrevocable and fully sublicensable right to use, reproduce, modify, adapt, publish, translate, create derivative works from, distribute and display such content throughout the world in any media now known or hereafter invented. You grant FantasyScroll and its affiliates the right to use the name you submit in connection with such content, if they so choose.
They do not specifically state otherwise in the submissions guidelines. I suppose a rejection could be taken as "stating otherwise."
Unfortunately, I submitted one story to them before spotting this. If I find they use it without payment I will change my opinion - I don't think they're actually doing this on purpose, but as it stands it at the very LEAST means they have your rights until they reject, and they could theoretically use your story without paying you.