Strange behavior on when I press button many times very quick in NODE.JS - node.js

Question

I have got 2 cards with 2 candidates, every candidate has a button where user can have a unique vote, the card have a box with total votes also, if the user make a vote for the first candidate, then the value of total in both cards is updated (in a card is substracted in another is added), . But when I press the button many times and very fast, the data returned by the backend is incorrect. Someone can explain what is happening please.
TEMPLATE OF COMPONENT IN ANGULAR
<mat-card class="example-card" *ngFor="let candidate of candidates; let i = index">
<mat-card-actions>
<button mat-raised-button class="button-vote" (click)="saveVote(candidate.userVotes[0], candidate)">
<mat-icon color="accent" aria-hidden="false" aria-label="Example home icon">pan_tool</mat-icon>
</button>
<div class="result" mat-fab>{{candidate.totalVotes}} votos</div>
</mat-card-actions>
</mat-card>
COMPONENENT.TS
export class CandidatesContainerComponent implements OnInit {
candidates!: any[]
constructor(
private candidatesService: CandidatesService,
) { }
ngOnInit(): void {
this.obtainCandidates()
}
obtainCandidates() {
this.candidatesService.getCandidates().subscribe((response: any) => {
this.candidates = response
})
}
saveVote(userVote: any, candidate: object | any) {
this.candidatesService.updateVote(candidate._id, userVote.thisChoosed).subscribe(response => {
if (response) {
this.obtainCandidates()
}
})
}
}
CONTROLLER IN NODE.JS
const updateVote = async ( req = request, res = response ) => {
const { candidateId, thisChoosed } = req.params
const query = thisChoosed === 'true' ? candidateId: { $ne:candidateId }
const previousVote = await Candidate.findOneAndUpdate(
{ _id:query },
{
'$set': { 'userVotes.$[el].thisChoose': false },
'$inc': { 'totalVotes': -1 }
},
{ arrayFilters: [
{"el.user": req.user._id }]
}
)
const newVote = await Candidate.findOneAndUpdate(
{ _id:candidateId },
{
'$set': { 'userVotes.$[el].thisChoose': true },
'$inc': { 'totalVotes': 1 }
},
{
arrayFilters: [ {"el.user": req.user._id }, ], new:true
}
)
res.json( newVote )
}
DATABASE
const VoteSchema = Schema({
user:{
type:Schema.ObjectId,
ref:'User',
required:[true, 'User is required - vote user']
},
thisChoosed:{
type:Boolean,
default:false
},
firstVote:{
type:Boolean,
default:true
}
})
const CandidateSchema = Schema({
names:{
type:String,
required:[true]
},
surnames:{
type:String,
required:[true]
},
userVotes:[VoteSchema],
totalVotes:{
type:Number,
default:0
},
})