[Vuejs]-Splice() wrong component in data array

there are couple of ways to achieve this but for now can you try these:

removePerson(key) {
            this.otherPersonArray = this.otherPersonArray.filter(person => {
                 return person.key === key;
             })
        }

OR

const index = this.otherPersonArray.indexOf(ele by key); // get index by key person key
if (index > -1) {
  this.otherPersonArray.splice(index, 1);
}

What I am understanding key is index here then you should follow this:

 var filtered = this.otherPersonArray.filter(function(value, index){ 
    return index !== key;
});

let me know if still it not working for you?

Here is example :

You can use Array.prototype.filter

removePerson(key) { 
  this.otherPerson = this.otherPersonArray.filter((x, i) => i !== key);
}