Skin syntax doesn't working

[PuchiGFX]

Tried this today:

function getTrimmedUUIDfromName(player: text) :: text:

  set {_uuid} to {_player} parsed as offline player's uuid
  set {_trimmed-uuid-parts::*} to {_uuid} split by "-"

  return join {_trimmed-uuid-parts::*} by ""

func "getSkin":

  set {_player} to parameter 1

  if "%{skin-cache::%{_player}%}%" is "{""signature"":"""",""value"":""""}":
    delete {skin-cache::%{_player}%}
  if {skin-cache::%{_player}%} isn't set:

    set {_trimmed-uuid} to getTrimmedUUIDfromName({_player})

    send request to "https://api.mineskin.org/generate/user/%{_trimmed-uuid}%"
    map json last response's body to {_skin-api::*}

    set {skin-cache::%{_player}%} to skin with value {_skin-api::data::texture::value} signature {_skin-api::data::texture::signature}
  set transient "skinOutput" to {skin-cache::%{_player}%}

  $ access
  set {_skin} to transient "skinOutput"
  return

command /skin [<text>]:
    trigger:
        access "getSkin" from arg-1
        set player's displayed skin to {_skin}
        reset player's displayed skin

The functions are from Nick/skin changer skript of @Snow-Pyon
No Errors on reload or in console, its just not working.
Spigot: 1.8.8
Skript dev 25
MundoSK: 1.7.5-BETA.10.8
Reqn: last version
SkJson: last version