Yeah, Aseprite changed its svg export routine not too long ago. I use a custom svg export script at https://github.com/behreajj/asepriteaddons instead. There are also online tools like https://flosscross.com/. Online tools specific to cross stitch will probably do a better job of matching digital color to material color.
Above is a demo video for the custom svg export that’s kinda old, but hopefully gets the idea across. Skip to about 1 min 44 sec in.