[Vuejs]-V-model with nested objects, accidentally reactivelly changing half array instead of single item

The problem is that you’re assigning an object as player.type in your options.

replace option with option.color (or some other non-object key) and it will work

TL;RD;

instead of

<select v-model="player.type">
  <option :value="option" v-for="option in playerOptions">{{option.color}}</option>
</select>

use

<select v-model="player.type">
  <option :value="option.color" v-for="option in playerOptions">{{option.color}}</option>
</select>