I'm also seeing this, using Vue / Card v.2.4

I also facing same issue
Enter more than 16 digit number
delete the last 3 digits..
In UI it shows 16 digit.. on form submit, the value is 17 digit.

Fixed by adding this.
<input md-input placeholder="Card number" type="tel" [(ngModel)]="model.cardNumber" name="number" #cardNumber='ngModel' required>

setCardNumber( $event) { this.model.cardNumber=$event.target.value; }

There is a "cards" array below of the card.js you can modify the number of length to 16 from there.

I fixed this issue by adding.

<input md-input placeholder="Card number" type="tel" [(ngModel)]="model.cardNumber" (keyup)="setCardNumber($event)" name="number" #cardNumber='ngModel' required>

` setCardNumber( $event) {

    this.model.cardNumber=$event.target.value;

}`