JSON slice information unusable when combining multiple input files in CLI about aseprite HOT 1 OPEN

{ "frames": {
   "spr_a.aseprite": {
    "frame": { "x": 0, "y": 0, "w": 32, "h": 32 },
    "rotated": false,
    "trimmed": false,
    "spriteSourceSize": { "x": 0, "y": 0, "w": 32, "h": 32 },
    "sourceSize": { "w": 32, "h": 32 },
    "duration": 100
   },
   "spr_b.aseprite": {
    "frame": { "x": 0, "y": 32, "w": 16, "h": 16 },
    "rotated": false,
    "trimmed": false,
    "spriteSourceSize": { "x": 0, "y": 0, "w": 16, "h": 16 },
    "sourceSize": { "w": 16, "h": 16 },
    "duration": 100
   }
 },
 "meta": {
  "app": "https://www.aseprite.org/",
  "version": "1.3.6-x64",
  "image": "atlas.png",
  "format": "RGBA8888",
  "size": { "w": 32, "h": 48 },
  "scale": "1",
  "slices": [
   { "name": "Slice 1", "color": "#0000ffff", "keys": [{ "frame": 0, "bounds": {"x": 16, "y": 16, "w": 6, "h": 12 } }] },
   { "name": "Slice 1", "color": "#0000ffff", "keys": [{ "frame": 0, "bounds": {"x": 1, "y": 1, "w": 7, "h": 7 } }] },
   { "name": "Slice 2", "color": "#0000ffff", "keys": [{ "frame": 0, "bounds": {"x": 8, "y": 8, "w": 7, "h": 7 } }] }
  ]
 }
}