Why do the chess pieces shrink to the top left corner？

[only0322]

<chessboard :onPromotion="promote" :free="ifFree" :orientation="boardColor" @onMove="getInfo"
                :fen="currentFen"/>

 async mounted() {
    if (location.protocol.indexOf('http') !== -1) {
      this.isDev = true
    }
    await this.getSetting()
    this.currentFen = this.openFen

  },

dont know how to fix it

[only0322]

openFen is the default fen like "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"