View error not updating when user interaction

Problem with Form (Data driven)

I have an array of objects (dashed block in the gif) that builds the view. The GIF below shows the error:

Each dashed block is a iteration of *ngFor="let price of priceOptionsList;let pr = index;" directive.

This is the object model:

    value       ? : number,
    description   : string,
    beginDate     : string,
    endDate       : string,

    periodActivated     : boolean

The button PERÍODO DE VIGÊNCIA changes the boolean value of periodActivated, that shows date/time inputs.

The button ADICIONAR VALOR adds an object in the array:

	"value"			: undefined, // In the view, it's displays the value of the position [0], error!
	"beginDate"		: '',
	"endDate"		: '',
	"description"	: '',
	"periodActivated" 	: false

When I click in the buttons, the view changes and not display the value in some inputs (see gif, description and date/time inputs get empty), but the model is the same, there is no changes!

I think it is a BUG, I am correct?

Solution found!

<div *ngFor="...; let i = index;">
    <ion-input [(NgModel)]="variable" [name]=" 'namehere' + i ">